Disk device

Abstract

The present invention provides a disk device capable of attaching a larger damper to a cover. A disk device according to an embodiment includes a base, a first cover, a second cover, and a damper. The base body has a bottom surface, a side wall protruding from the bottom surface in a first direction, and a support surface provided at an end portion of the side wall in the first direction, and a storage space in which a magnetic disk is disposed is provided on the inner sides of the bottom surface and the side wall. The first cover is attached to the base so as to close the storage space. The second cover covers the first cover, is supported by the support surface, and is coupled to the base. The damper has a restraint layer located between the first cover and the second cover, and a viscoelastic body interposed between the first cover and the restraint layer. The restraint layer has a thin portion provided along the support surface, and a thick portion connected to the thin portion.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2023-152223 (filing date: September 20, 2023). This application incorporates all the contents of the basic application by reference. Technical Field

[0002] The present embodiment relates to a disk device. Background Art

[0003] A disk device such as a hard disk drive (HDD) includes a disk, a magnetic head for reading and writing information on the disk, and a housing for accommodating various components. In addition, in some disk devices, the housing includes a base, a first cover for closing the space inside the base, and a second cover covering the first cover.

[0004] The disk device may further include a damper that attenuates vibration by deformation of a viscoelastic body. The damper is attached to the first cover between the first cover and the second cover, for example.

[0005] The size of the disk device is limited by various conditions. In the design of the disk device, it is sometimes difficult to arrange a damping member of a desired size between the first cover and the second cover due to these restrictions. Summary of the invention

[0006] The embodiment of the present invention provides a disk device capable of mounting a larger damping member on a cover.

[0007] The disk device of this embodiment has a magnetic disk, a base, a first cover, a second cover and a damping member. The base has a bottom surface facing the magnetic disk, a side wall protruding from the bottom surface in the first direction and surrounding the magnetic disk, and a supporting surface arranged at the end of the side wall in the first direction, and a storage space for arranging the magnetic disk is arranged on the inner side of the bottom surface and the side wall. The first cover is installed on the base in a manner of blocking the storage space. The second cover covers the first cover and is supported by the supporting surface and is combined with the base. The damping member has a constraint layer located between the first cover and the second cover, and a viscoelastic body between the first cover and the constraint layer. The constraint layer has a thin-walled portion arranged along the supporting surface, and a thick-walled portion connected to the thin-walled portion and thicker than the thin-walled portion in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0009] Figure 2 This is an exemplary cross-sectional view schematically showing one end portion of the HDD according to the above embodiment.

[0010] Figure 3 This is an exemplary cross-sectional view schematically showing the other end portion of the HDD according to the above embodiment.

[0011] Figure 4 This is an exemplary perspective view showing the HDD with the cover and the protective member removed according to the above embodiment.

[0012] Figure 5 This is an exemplary perspective view showing the HDD with the inner cover, outer cover, and protective member removed according to the above embodiment.

[0013] Figure 6 1 is an illustrative top view showing the magnet and the confinement layer of the above embodiment.

[0014] Description of Reference Numerals

[0015] 10…hard disk drive (HDD); 15…base; 16…inner cover; 17…outer cover; 18, 19…protective member; 21a…bottom surface; 22…side wall; 22a…end surface; 31…disk; 34…voice coil motor (VCM); 35…slide; 45…head; 46…suspension; 52…magnet; 52a, 52b…magnetic pole; 52c…boundary; 81, 85…upper wall; 91, 92…damping member; 101, 111…constraint layer; 102, 112…viscoelastic body; 105, 115…thick wall portion; 106, 116…thin wall portion; 107…first thin wall portion; 108…second thin wall portion; S…storage space; B…weld; A1, A2…adhesive. DETAILED DESCRIPTION

[0016] Below, refer to Figures 1 to 6 To illustrate an embodiment. In addition, in this specification, the constituent elements involved in the embodiment and the description of the element are sometimes recorded in multiple expressions. The constituent elements and their descriptions are examples and are not limited by the descriptions in this specification. The constituent elements can also be identified by names different from the names in this specification. In addition, the constituent elements can also be described by expressions different from the descriptions in this specification.

[0017] In the following description, “suppress” is defined as, for example, preventing the occurrence of an event, action, or influence, or reducing the degree of an event, action, or influence.

[0018] Figure 1 1 is an illustrative perspective view showing a hard disk drive (HDD) 10 according to one embodiment. The HDD 10 is an example of a disk device, and may also be called an electronic device, a storage device, an external storage device, or a magnetic disk device. The HDD 10 has a housing 11 that accommodates various components.

[0019] As shown in the drawings, in this specification, for convenience, an X-axis, a Y-axis, and a Z-axis are defined. The X-axis, the Y-axis, and the Z-axis are orthogonal to each other. The X-axis is set along the width of the HDD 10. The Y-axis is set along the length of the HDD 10. The Z-axis is set along the thickness of the HDD 10.

[0020] In addition, in this specification, the X direction, the Y direction, and the Z direction are defined. The X direction is a 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 a 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. The Z direction is a direction along the Z axis, including 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.

[0021] Figure 2 2 is an exemplary cross-sectional view schematically showing an end portion of the HDD 10 in the -Y direction of the present embodiment. Figure 2 As shown, the housing 11 includes a base 15, an inner cover 16, an outer cover 17, and a protector 18. The inner cover 16 is an example of a first cover. The outer cover 17 is an example of a second cover. The protector 18 is an example of a third cover and may also be referred to as a protective cover.

[0022] Figure 3 2 is an exemplary cross-sectional view schematically showing the end of the HDD 10 in the +Y direction of the present embodiment. Figure 3 As shown in FIG. 1 , the housing 11 further includes a protector 19. The protector 19 is also an example of a third cover. In addition, the housing 11 may omit the protectors 18 and 19.

[0023] The base 15 and the outer cover 17 are made of metal such as aluminum alloy. The inner cover 16, the protective member 18, and the protective member 19 are made of metal such as non-magnetic stainless steel. That is, the base 15, the inner cover 16, the outer cover 17, the protective member 18, and the protective member 19 are non-magnetic. In addition, the base 15, the inner cover 16, the outer cover 17, the protective member 18, and the protective member 19 can also be made of other materials and can be ferromagnetic.

[0024] The substrate 15 is a bottomed container that is open in the +Z direction. Figure 1 As shown, the base 15 extends in the Y direction. In other words, the length of the base 15 in the Y direction is longer than the length of the base 15 in the X direction and longer than the length of the base 15 in the Z direction.

[0025] Figure 4 This is an exemplary perspective view showing the HDD 10 with the cover 17 and the protection members 18 and 19 removed according to the present embodiment. Figure 51 is an exemplary perspective view showing the HDD 10 after removing the inner cover 16, the outer cover 17, and the protective members 18 and 19 according to the present embodiment. Figure 5 As shown, the base body 15 has a bottom wall 21 and side walls 22 .

[0026] The bottom wall 21 is formed in a substantially rectangular (quadrilateral) plate shape extending along the XY plane. The bottom wall 21 has a bottom surface 21a. The bottom surface 21a is generally oriented in the substantially +Z direction. The bottom surface 21a may have projections and depressions.

[0027] The side wall 22 protrudes from the bottom surface 21a in the approximately +Z direction. The +Z direction is an example of the first direction. The side wall 22 is formed in a substantially rectangular frame shape. The bottom surface 21a and the frame-shaped side wall 22 form (define, partition) a storage space S inside the base 15. In other words, the storage space S is provided inside the bottom surface 21a and the side wall 22. The storage space S is open to the outside of the base 15 at the end of the base 15 in the +Z direction.

[0028] like Figure 2 As shown, the side wall 22 has an end surface 22a, a mounting surface 22b, an inner surface 22c, and an intermediate surface 22d. In addition, the side wall 22 is not limited to this example. The end surface 22a is an example of a support surface.

[0029] The end surface 22a is provided at the end of the side wall 22 in the +Z direction. The end surface 22a is formed substantially flat and faces substantially in the +Z direction. The end surface 22a is formed in a substantially rectangular frame shape. In other words, the end surface 22a is formed in an endless shape.

[0030] like Figure 5 As shown, the end surface 22a has two short sides 22e and 22f and two long sides 22g and 22h. The short side 22e is located at the end of the base 15 in the -Y direction. The short side 22f is located at the end of the base 15 in the +Y direction. The short sides 22e and 22f extend approximately in the X direction. The long side 22g is located at the end of the base 15 in the -X direction. The long side 22h is located at the end of the base 15 in the +X direction. The long sides 22g and 22h extend approximately in the Y direction.

[0031] The mounting surface 22b is surrounded by the end surface 22a in the projection plane projected in the Z direction. The mounting surface 22b is located near the end surface 22a in the Z direction and closer to the bottom surface 21a than the end surface 22a. In other words, the mounting surface 22b is recessed from the end surface 22a in the substantially -Z direction.

[0032] The mounting surface 22b is formed to be substantially flat and faces substantially in the +Z direction. The mounting surface 22b is formed in a substantially rectangular frame shape. The mounting surface 22b is not limited to this example. A plurality of screw holes 25 are provided on the mounting surface 22b.

[0033] The inner surface 22c is provided between the inner edge of the mounting surface 22b and the bottom surface 21a. The inner surface 22c faces the inside of the storage space S. The intermediate surface 22d is provided between the inner edge of the end surface 22a and the outer edge of the mounting surface 22b.

[0034] In other words, the side wall 22 has a rib 24 that protrudes from the mounting surface 22b in the substantially +Z direction. The rib 24 is formed in a substantially rectangular frame shape. The rib 24 has an end surface 22a and an intermediate surface 22d.

[0035] like Figure 4 As shown, the housing 11 further includes a plurality of screws 26. The inner cover 16 is supported on the mounting surface 22b, for example, and is mounted on the mounting surface 22b by the screws 26. Thus, the inner cover 16 is mounted on the base 15 in a manner to substantially airtightly seal the storage space S. A sealing gasket is provided between the inner cover 16 and the mounting surface 22b, for example.

[0036] like Figure 2 As shown, the outer cover 17 covers the inner cover 16 via a gap G and is supported by the end surface 22a. In this embodiment, the edge of the outer cover 17 is joined to the end surface 22a by welding over the entire circumference. As a result, the outer cover 17 is joined to the base 15 in a manner of airtightly sealing the storage space S. That is, the inner cover 16 and the outer cover 17 seal the storage space S. The housing 11 has a weld B formed by welding the outer cover 17 to the base 15. The weld B is an example of a portion formed by the second cover being joined to the base.

[0037] The outer cover 17 may also be coupled to other parts of the base 15. For example, the outer cover 17 may have a portion surrounding the side wall 22, and may be coupled to the side wall 22 at this portion. In addition, the outer cover 17 may also be coupled to the base 15 by other methods such as bonding.

[0038] like Figure 4 As shown, a vent 27 is provided in the inner cover 16. Figure 1 As shown, the cover 17 is provided with ventilation holes 28. When the HDD 10 is assembled, the air in the storage space S is extracted from the ventilation holes 27 and 28. Furthermore, the storage space S is filled with a gas different from the air.

[0039] The gas filled into the storage space S is, for example, a low-density gas having a density lower than that of air, an inert gas having low reactivity, etc. For example, helium is filled into the storage space S. In addition, the storage space S may be filled with other fluids.

[0040] The vent 28 of the outer cover 17 is blocked by a seal 29. The seal 29 seals the vent 28 airtightly, and prevents the gas filled in the storage space S from leaking through the vents 27 and 28.

[0041] The protector 18 is located at the end of the housing 11 in the -Y direction. The protector 18 covers the end of the side wall 22 in the -Y direction, the end of the cover 17 in the -Y direction, and the weld B. The -Y direction is a direction orthogonal to the +Z direction and is an example of a second direction.

[0042] The protection member 19 is located at the end of the housing 11 in the +Y direction. The protection member 19 covers the end of the side wall 22 in the +Y direction, the end of the outer cover 17 in the +Y direction, and the weld B.

[0043] like Figure 5 As shown, the HDD 10 further includes a plurality of magnetic disks 31, a spindle motor 32, a head stack assembly (HSA) 33, and a voice coil motor (VCM) 34. The VCM 34 is an example of an actuator.

[0044] The magnetic disk 31 , the spindle motor 32 , the HSA 33 , and the VCM 34 are arranged in the storage space S. Therefore, the bottom surface 21 a of the base 15 faces the magnetic disk 31 , the spindle motor 32 , the HSA 33 , and the VCM 34 . The side wall 22 surrounds the magnetic disk 31 , the spindle motor 32 , the HSA 33 , and the VCM 34 .

[0045] The magnetic disk 31 is, for example, a recording medium having magnetic recording layers on the upper surface and the lower surface. The diameter of the magnetic disk 31 is, for example, 3.5 inches. The magnetic disk 31 is not limited to this example.

[0046] The magnetic disks 31 are arranged along the XY plane. The plurality of magnetic disks 31 are overlapped with each other at intervals in the Z direction. The HDD 10 of the present embodiment has ten or more magnetic disks 31 arranged in the Z direction. The number of magnetic disks 31 is not limited to this example.

[0047] The spindle motor 32 supports and rotates the plurality of magnetic disks 31. The plurality of magnetic disks 31 are held on the hub of the spindle motor 32 by, for example, a clamp spring. The spindle motor 32 is attached to, for example, the bottom wall 21 of the base 15 and supported by the inner cover 16.

[0048] The HSA 33 has a carriage 35 and a plurality of head gimbal assemblies (HGAs) 36. The carriage 35 has an actuator block 41, a plurality of arms 42, and a holder 43.

[0049] For example, the support shaft 44 is provided at a position away from the magnetic disk 31 in a direction substantially perpendicular to the Z direction. The support shaft 44 extends substantially in the +Z direction from the bottom wall 21 and is supported by the inner cover 16. The actuator block 41 is rotatably mounted on the support shaft 44 via a bearing, for example.

[0050] The plurality of arms 42 protrude from the actuator block 41 substantially parallel to a direction substantially orthogonal to the Z direction. The plurality of arms 42 are arranged at intervals in the Z direction. The plurality of arms 42 are each formed into a plate shape capable of entering between two adjacent disks among the plurality of disks 31. The retainer 43 protrudes from the actuator block 41 in the opposite direction of the arm 42.

[0051] Each of the plurality of HGAs 36 includes a magnetic head 45 and a suspension 46. The magnetic head 45 may also be called a slider. The magnetic head 45 records and reproduces information on the recording layer of the magnetic disk 31. In other words, the magnetic head 45 reads and writes information on the magnetic disk 31.

[0052] The suspension 46 includes, for example, a base plate, a load beam extending from the base plate, and a flexure mounted on the base plate and the load beam. The flexure is a flexible printed circuit board (FPC).

[0053] The base plate is mounted on the top of the arm 42. The magnetic head 45 is mounted on the flexure. Thus, the magnetic head 45 is mounted on the suspension 46. Furthermore, the suspension 46 is mounted on the carriage 35.

[0054] The VCM 34 includes a coil 51, a magnet 52, and a yoke 53. The coil 51 is held by the holder 43 of the carriage 35. The magnet 52 is, for example, a permanent magnet, and is attached to the base 15 via the yoke 53.

[0055] When the coil 51 is energized, the carriage 35 rotates about the support shaft 44 due to the electromagnetic force generated by the current in the coil 51 and the magnetic field of the magnet 52. In this way, the VCM 34 rotates the carriage 35 and moves the magnetic head 45 mounted on the carriage 35 via the suspension 46 to a desired position.

[0056] like Figure 4 As shown, the inner cover 16 has a central portion 61 and a peripheral portion 62. The central portion 61 is a portion of the inner cover 16 formed in a substantially rectangular plate shape. The central portion 61 is provided with a vent 27 and supports the spindle motor 32 and the support shaft 44. The peripheral portion 62 is a portion of the inner cover 16 formed in a substantially rectangular frame shape. The peripheral portion 62 surrounds the central portion 61. Figure 2 As shown, the peripheral edge portion 62 is supported by the mounting surface 22 b of the side wall 22 and is mounted on the mounting surface 22 b by screws 26 .

[0057] In the Z direction, the thickness of the central portion 61 and the thickness of the peripheral portion 62 are substantially equal. The peripheral portion 62 is closer to the bottom surface 21a of the bottom wall 21 than the central portion 61. For example, the inner cover 16 is bent by, for example, press working, so that the central portion 61 protrudes from the inner edge of the peripheral portion 62 substantially in the +Z direction.

[0058] like Figure 4 As shown, the center portion 61 has two mounting surfaces 61a and 61b and an inclined surface 61c. The mounting surfaces 61a and 61b are formed substantially flat and face substantially in the +Z direction. The mounting surfaces 61a and 61b face the outer cover 17 across the gap G between the inner cover 16 and the outer cover 17.

[0059] The mounting surface 61a is provided at the end of the central portion 61 in the -X direction and the -Y direction. The magnet 52 of the VCM 34 overlaps with the mounting surface 61a in the +Z direction. In other words, at least a portion of the mounting surface 61a is provided at a position away from or adjacent to the magnet 52 in the +Z direction. In addition, the mounting surface 61a may also be provided at other positions.

[0060] The mounting surface 61b is provided at the end of the center portion 61 in the +Y direction. The magnetic disk 31 overlaps with the mounting surface 61b in the +Z direction. In addition, the mounting surface 61b may be provided at other positions.

[0061] The inclined surface 61c is adjacent to the mounting surface 61b and faces the housing 17 via a gap G. In the present embodiment, the inclined surface 61c is located around the spindle motor 32 and is continuous with the mounting surface 61b. The inclined surface 61c extends obliquely from the mounting surface 61b toward the housing 17.

[0062] like Figure 2 As shown in FIG. 1 , the outer cover 17 has a central portion 71 and a peripheral portion 72. The central portion 71 is a portion of the outer cover 17 formed in a substantially rectangular plate shape. Figure 1 As shown in FIG. 1 , the ventilation hole 28 is provided in the central portion 71. The peripheral portion 72 is a part of the outer cover 17 formed in a substantially rectangular frame shape. The peripheral portion 72 surrounds the central portion 71. Figure 2 As shown, the peripheral edge portion 72 is supported by the end surface 22a of the side wall 22 and is joined to the end surface 22a by welding.

[0063] In the Z direction, the thickness of the central portion 71 is substantially equal to the thickness of the peripheral portion 72. The peripheral portion 72 is closer to the bottom surface 21a of the bottom wall 21 than the central portion 71. For example, the outer cover 17 is curved so that the central portion 71 protrudes from the inner edge of the peripheral portion 72 in the substantially +Z direction. In addition, the peripheral portion 72 may extend obliquely from the central portion 71 toward the end surface 22a of the side wall 22.

[0064] The central portion 71 has an outer surface 71a and an inner surface 71b. The outer surface 71a is provided at the end of the outer cover 17 in the +Z direction. The outer surface 71a is formed to be substantially flat and faces substantially in the +Z direction. The inner surface 71b is located on the opposite side of the outer surface 71a. The inner surface 71b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 71b faces the central portion 61 of the inner cover 16 with a gap G therebetween.

[0065] The peripheral portion 72 has a concave surface 72a and an inner surface 72b. The concave surface 72a is connected to the outer surface 71a of the central portion 71 and is generally oriented in the +Z direction. In the present embodiment, the concave surface 72a is formed to be substantially flat at a position closer to the bottom surface 21a of the bottom wall 21 than the outer surface 71a and is oriented in the +Z direction.

[0066] like Figure 1 As shown, the concave surface 72a forms (defines, partitions) two concave portions 75 and 76. The concave portion 75 is recessed from the outer surface 71a at the end of the outer cover 17 in the -Y direction. The concave portion 76 is recessed from the outer surface 71a at the end of the outer cover 17 in the +Y direction. The concave portions 75 and 76 extend substantially in the X direction and are provided over both ends of the outer cover 17 in the X direction.

[0067] like Figure 2 As shown, the inner surface 72b is located on the opposite side of the concave surface 72a. The inner surface 72b is supported by the end surface 22a of the side wall 22. The inner surface 72b faces the central portion 61 and the peripheral portion 62 of the inner cover 16. The mounting surfaces 61a and 61b of the central portion 61 face the inner surface 71b of the central portion 71 and the inner surface 72b of the peripheral portion 72 of the outer cover 17, respectively.

[0068] The gap G between the inner cover 16 and the outer cover 17 includes a wide gap GW and a narrow gap GN. The gap GW is a gap between the mounting surface 61a or the mounting surface 61b of the central portion 61 of the inner cover 16 and the inner surface 71b of the central portion 71 of the outer cover 17. The gap GN is a gap between the mounting surface 61a or the mounting surface 61b of the central portion 61 of the inner cover 16 and the inner surface 72b of the peripheral portion 72 of the outer cover 17.

[0069] In the Z direction (+Z direction), the distance between the mounting surface 61a or the mounting surface 61b and the inner surface 71b is greater than the distance between the mounting surface 61a or the mounting surface 61b and the inner surface 72b. Therefore, in the Z direction, the gap GW is wider than the gap GN. The gap GW and the gap GN are connected to each other.

[0070] The protector 18 has an upper wall 81 and an end wall 82. The upper wall 81 is an example of a covering wall. The upper wall 81 is disposed in the recessed portion 75 and extends substantially in the X direction along the recessed portion 75. Therefore, the upper wall 81 covers the peripheral edge portion 72 of the outer cover 17.

[0071] The upper wall 81 has an upper surface 81a and an inner surface 81b. The upper surface 81a is formed to be substantially flat and faces substantially in the +Z direction. The inner surface 81b is located on the opposite side of the upper surface 81a. The inner surface 81b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 81b faces the concave surface 72a of the peripheral edge portion 72.

[0072] The inner surface 81b of the upper wall 81 is attached to the concave surface 72a of the peripheral portion 72 by, for example, adhesive A1. Adhesive A1 is, for example, a synthetic adhesive. Adhesive A1 is not limited to this example, and may be other substances such as double-sided tape that can bond a plurality of components to each other.

[0073] In the Z direction (+Z direction), the depth L1 of the recessed portion 75 is greater than the sum L2 of the thickness of the upper wall 81 and the thickness of the adhesive A1. Therefore, the upper wall 81 does not protrude beyond the outer surface 71a of the central portion 71 to the outside of the recessed portion 75. The depth L1 is, for example, the distance in the Z direction between the outer surface 71a and the portion of the recessed surface 72a closest to the bottom surface 21a of the bottom wall 21. The sum L2 of the thickness is, for example, the distance in the Z direction between the upper surface 81a and the portion of the recessed surface 72a to which the adhesive A1 is attached.

[0074] The end wall 82 extends from the end of the upper wall 81 in the −Y direction substantially in the −Z direction. That is, the cross section of the protector 18 including the upper wall 81 and the end wall 82 is substantially L-shaped. The end wall 82 covers the side wall 22 .

[0075] like Figure 3 As shown, the protection member 19 has an upper wall 85 and an end wall 86. The upper wall 85 is an example of a covering wall. The upper wall 85 is arranged in the recessed portion 76 and extends substantially in the X direction along the recessed portion 76. Therefore, the upper wall 85 covers the peripheral edge portion 72 of the outer cover 17.

[0076] The upper wall 85 has an upper surface 85a and an inner surface 85b. The upper surface 85a is formed to be substantially flat and faces substantially in the +Z direction. The inner surface 85b is located on the opposite side of the upper surface 85a. The inner surface 85b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 85b faces the concave surface 72a of the peripheral portion 72. The inner surface 85b of the upper wall 85 is attached to the concave surface 72a of the peripheral portion 72, for example, by an adhesive A2. The adhesive A2 is, for example, a synthetic adhesive.

[0077] The depth of the recess 76 in the Z direction (+Z direction) is equal to or greater than the sum of the thickness of the upper wall 85 and the thickness of the adhesive A2. Therefore, the upper wall 85 does not protrude beyond the outer surface 71a of the center portion 71 to the outside of the recess 75.

[0078] The end wall 86 extends from the end of the upper wall 85 in the +Y direction to substantially the −Z direction. That is, the cross section of the protector 19 including the upper wall 85 and the end wall 86 is substantially L-shaped. The end wall 86 covers the side wall 22 .

[0079] like Figure 4 As shown, the HDD 10 of the present embodiment further includes two dampers 91 and 92 . The dampers 91 and 92 are arranged in a gap G between the inner cover 16 and the outer cover 17 .

[0080] like Figure 2 As shown, the damping member 91 includes a constrained layer 101 and a viscoelastic material (VEM) 102. The damping member 91 is not limited to this example. The constrained layer 101 may also be referred to as a vibration damping plate.

[0081] The constrained layer 101 is made of a metal such as ferromagnetic stainless steel. That is, the constrained layer 101 is a ferromagnetic body (magnetic body). Ferromagnetic stainless steel is, for example, SUS400 stainless steel (ferritic stainless steel and martensitic stainless steel) in Japanese industrial standards (JIS). Specifically, the constrained layer 101 is made of SUS430. In addition, the constrained layer 101 can also be made of other ferromagnetic bodies, or a non-magnetic body.

[0082] The thermal expansion coefficient of the material of the inner cover 16 is closer to that of the material of the substrate 15 than that of the material of the constraining layer 101. That is, the inner cover 16 and the constraining layer 101 are both made of stainless steel, but the inner cover 16 is made of stainless steel of a type having a thermal expansion coefficient close to that of the substrate 15.

[0083] The constraining layer 101 is located in the gap G between the inner cover 16 and the outer cover 17 and is formed in a plate shape arranged along the XY plane. The viscoelastic body 102 is interposed between the mounting surface 61a of the central portion 61 of the inner cover 16 and the constraining layer 101. Thus, the viscoelastic body 102 mounts the constraining layer 101 on the mounting surface 61a.

[0084] The constrained layer 101 has a plurality of portions having different thicknesses. The constrained layer 101 of the present embodiment has a thick wall portion 105 and a thin wall portion 106. The thick wall portion 105 and the thin wall portion 106 are integrally formed and connected to each other. In the Z direction (+Z direction), the thick wall portion 105 is thicker than the thin wall portion 106, and the thin wall portion 106 is thinner than the thick wall portion 105.

[0085] The thick portion 105 is located between the mounting surface 61a of the center portion 61 of the inner cover 16 and the inner surface 71b of the center portion 71 of the outer cover 17. That is, the thick portion 105 is located in the wide gap GW. The thick portion 105 has an upper surface 105a and an inner surface 105b.

[0086] The upper surface 105a is formed to be substantially flat and faces substantially in the +Z direction. The upper surface 105a faces the inner surface 71b of the central portion 71. The inner surface 105b is located on the opposite side of the upper surface 105a. The inner surface 105b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 105b faces the mounting surface 61a of the central portion 61.

[0087] like Figure 4 As shown, the thick wall portion 105 also has two edges 105c and 105d. The edges 105c and 105d can also be called sides. The edge 105c is provided at the end of the thick wall portion 105 in the -Y direction and extends approximately in the X direction. The edge 105d is provided at the end of the thick wall portion 105 in the -X direction and extends approximately in the Y direction.

[0088] The edge 105c faces the portion of the rib 24 having the short side 22e and extends along the short side 22e. The edge 105d faces the portion of the rib 24 having the long side 22g and extends along the long side 22g.

[0089] The thin portion 106 is located between the end surface 22a of the side wall 22 and the thick portion 105. In other words, the thin portion 106 is located between the weld B and the thick portion 105. The thin portion 106 is provided along a portion of the end surface 22a of the side wall 22 close to the mounting surface 61a and the thick portion 105.

[0090] like Figure 2 As shown in FIG. 1 , the thin-walled portion 106 is located between the mounting surface 61a of the central portion 61 of the inner cover 16 and the inner surface 72b of the peripheral portion 72 of the outer cover 17. That is, the thin-walled portion 106 is located in the narrow gap GN. Figure 4 As shown, the thin-walled portion 106 includes a first thin-walled portion 107 and a second thin-walled portion 108 .

[0091] The first thin-walled portion 107 protrudes from the edge 105c of the thick-walled portion 105 in the substantially -Y direction. Therefore, the first thin-walled portion 107 is located between the end of the inner cover 16 in the -Y direction and the thick-walled portion 105. The first thin-walled portion 107 extends substantially in the X direction along the short side portion 22e. In other words, the first thin-walled portion 107 extends substantially parallel to the short side portion 22e.

[0092] The second thin portion 108 protrudes substantially in the -X direction from the edge 105d of the thick portion 105. Therefore, the second thin portion 108 is located between the end of the inner cover 16 in the -X direction and the thick portion 105. The -X direction is a direction perpendicular to the +Z direction and perpendicular to the -Y direction, and is an example of a third direction.

[0093] The second thin-walled portion 108 extends along the long side 22g in the approximate Y direction. In other words, the second thin-walled portion 108 extends approximately parallel to the long side 22g. The end of the first thin-walled portion 107 in the -X direction and the end of the second thin-walled portion 108 in the -Y direction are connected to each other. Therefore, the thin-walled portion 106 is formed in a substantially L-shape.

[0094] The length (width) of the first thin portion 107 in the Y direction (-Y direction) is greater than the length (width) of the second thin portion 108 in the X direction (-X direction). The widths of the first thin portion 107 and the second thin portion 108 are not limited to this example.

[0095] like Figure 2 As shown in FIG. 1 , the first thin-walled portion 107 of the thin-walled portion 106 overlaps with the upper wall 81 of the protector 18 in the +Z direction. On the other hand, the thick-walled portion 105 and the second thin-walled portion 108 are separated from the protector 18 in a direction perpendicular to the Z direction (+Z direction). In other words, the thick-walled portion 105 and the second thin-walled portion 108 do not overlap with the protector 18.

[0096] The thin-walled portion 106 further includes an upper surface 106a and an inner surface 106b. The first thin-walled portion 107 and the second thin-walled portion 108 each include a portion of the upper surface 106a and a portion of the inner surface 106b.

[0097] Upper surface 106a is formed substantially flat and faces substantially in the +Z direction. Upper surface 106a faces inner surface 71b of central portion 71 and inner surface 72b of peripheral edge portion 72. Upper surface 106a of thin portion 106 is closer to bottom surface 21a of bottom wall 21 than upper surface 105a of thick portion 105.

[0098] The inner surface 106b is located on the opposite side of the upper surface 106a. The inner surface 106b is formed to be substantially flat and faces substantially the -Z direction. The inner surface 106b faces the mounting surface 61a of the central portion 61. The inner surface 105b of the thick wall portion 105 and the inner surface 106b of the thin wall portion 106 form substantially the same plane and are continuous with each other.

[0099] The viscoelastic body 102 is interposed between the inner surface 105b of the thick wall portion 105 and the mounting surface 61a of the central portion 61 of the inner cover 16. Furthermore, the viscoelastic body 102 is interposed between the inner surface 106b of the thin wall portion 106 and the mounting surface 61a of the central portion 61 of the inner cover 16. That is, both the thick wall portion 105 and the thin wall portion 106 are mounted on the mounting surface 61a via the viscoelastic body 102.

[0100] In the Z direction (+Z direction), the difference L3 between the thickness of the thick portion 105 and the thickness of the thin portion 106 is greater than the sum L2 of the thickness of the upper wall 81 and the thickness of the adhesive A1. The thickness difference L3 is the distance between the upper surface 105a of the thick portion 105 and the upper surface 106a of the thin portion 106 in the Z direction.

[0101] Adhesive A3 is attached to the inner surface 71b of the central portion 71 and the inner surface 72b of the peripheral portion 72 of the outer cover 17. Adhesive A3 is, for example, a double-sided tape. Adhesive A3 attaches the inner surface 71b of the central portion 71 to the upper surface 105a of the thick-walled portion 105. Adhesive A3 attaches the inner surface 72b of the peripheral portion 72 to the upper surface 106a of the thin-walled portion 106.

[0102] Figure 6 FIG. 1 is an illustrative top view showing the magnet 52 and the constrained layer 101 of this embodiment. Figure 6 As shown, the entire magnet 52 overlaps with the constrained layer 101 in the +Z direction. In addition, a portion of the magnet 52 may not overlap with the constrained layer 101.

[0103] The magnet 52 has two magnetic poles 52a and 52b and a boundary 52c. In addition, the magnet 52 may have three or more magnetic poles. The two magnetic poles 52a and 52b are adjacent to each other in a direction orthogonal to the Z direction (+Z direction). The magnetic pole 52a is one of the N pole and the S pole, and the magnetic pole 52b is the other. The boundary 52c is the boundary between the two magnetic poles 52a and 52b.

[0104] In this embodiment, most of the magnetic poles 52a and 52b overlap with the thick wall portion 105 in the +Z direction. In addition, the entire boundary 52c overlaps with the thick wall portion 105 in the +Z direction. In addition, the magnetic poles 52a and 52b and a part of the boundary 52c may overlap with the thin wall portion 106 or may not overlap with the constrained layer 101.

[0105] like Figure 3 As shown, the damping member 92 includes a constrained layer 111 and a viscoelastic body 112. The damping member 92 is not limited to this example. The constrained layer 111 is the same as the constrained layer 101 of the damping member 91 and is made of a metal such as ferromagnetic stainless steel.

[0106] The constraining layer 111 is located in the gap G between the inner cover 16 and the outer cover 17 and is formed in a plate shape arranged along the XY plane. The viscoelastic body 112 is interposed between the mounting surface 61b of the central portion 61 of the inner cover 16 and the constraining layer 111. Thus, the viscoelastic body 112 mounts the constraining layer 111 on the mounting surface 61b.

[0107] The constrained layer 111 has a thick portion 115 and two thin portions 116, 117. The thick portion 115 and the thin portions 116, 117 are integrally formed and connected to each other. The thick portion 115 is thicker than the thin portions 116, 117 in the Z direction (+Z direction).

[0108] The thick portion 115 is located between the mounting surface 61b of the center portion 61 of the inner cover 16 and the inner surface 71b of the center portion 71 of the outer cover 17. That is, the thick portion 115 is located in the wide gap GW. The thick portion 115 has an upper surface 115a and an inner surface 115b.

[0109] The upper surface 115a is formed to be substantially flat and faces substantially in the +Z direction. The upper surface 115a faces the inner surface 71b of the central portion 71. The inner surface 115b is located on the opposite side of the upper surface 115a. The inner surface 115b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 115b faces the mounting surface 61b of the central portion 61.

[0110] like Figure 4 As shown, the thick wall portion 115 further has an edge 115c. The edge 115c is provided at the end of the thick wall portion 115 in the +Y direction and extends substantially in the X direction. The edge 115c faces the portion of the rib 24 having the short side 22f and extends along the short side 22f.

[0111] The thin portion 116 is located between the end surface 22a of the side wall 22 and the thick portion 115. In other words, the thin portion 116 is located between the weld B and the thick portion 115. The thin portion 116 is provided along a portion of the end surface 22a of the side wall 22 close to the mounting surface 61b and the thick portion 115.

[0112] like Figure 3 As shown, the thin-walled portion 116 is located between the mounting surface 61b of the central portion 61 of the inner cover 16 and the inner surface 72b of the peripheral edge portion 72 of the outer cover 17. That is, the thin-walled portion 116 is located in the narrow gap GN.

[0113] The thin-walled portion 116 protrudes in the substantially +Y direction from the edge 115c of the thick-walled portion 115. Therefore, the thin-walled portion 116 is located between the end of the inner cover 16 in the +Y direction and the thick-walled portion 115. The thin-walled portion 116 extends substantially in the X direction along the short side portion 22f. In other words, the thin-walled portion 116 extends substantially parallel to the short side portion 22f.

[0114] The thin-walled portion 116 has an upper surface 116a and an inner surface 116b. The upper surface 116a is formed to be substantially flat and faces substantially in the +Z direction. The upper surface 116a faces the inner surface 71b of the central portion 71 and the inner surface 72b of the peripheral portion 72. The upper surface 116a of the thin-walled portion 116 is closer to the bottom surface 21a of the bottom wall 21 than the upper surface 115a of the thick-walled portion 115.

[0115] The inner surface 116b is located on the opposite side of the upper surface 116a. The inner surface 116b is formed to be substantially flat and faces substantially the -Z direction. The inner surface 116b faces the mounting surface 61b of the central portion 61. The inner surface 115b of the thick wall portion 115 and the inner surface 116b of the thin wall portion 116 form substantially the same plane and are continuous with each other.

[0116] The thin portion 117 protrudes from the thick portion 115 toward the inclined surface 61c of the center portion 61 of the inner cover 16. The thick portion 115 is located between the thin portion 116 and the thin portion 117. In addition, the thin portion 117 may be omitted.

[0117] The thin portion 117 has an upper surface 117a and an inner surface 117b. The upper surface 117a is formed to be substantially flat and faces substantially in the +Z direction. The upper surface 117a faces the inner surface 71b of the central portion 71. The upper surface 115a of the thick portion 115 and the upper surface 117a of the thin portion 117 form substantially the same plane and are continuous with each other.

[0118] The inner surface 117b is located on the opposite side of the upper surface 117a. The inner surface 117b is formed to be substantially flat and faces substantially in the -Z direction. The inner surface 117b faces the inclined surface 61c of the central portion 61. The inner surface 117b of the thin-walled portion 117 is further away from the bottom surface 21a of the bottom wall 21 than the inner surface 115b of the thick-walled portion 115.

[0119] The thin-walled portion 116 overlaps with the upper wall 85 of the protective member 19 in the +Z direction. In the Z direction, the difference between the thickness of the thick-walled portion 115 and the thickness of the thin-walled portion 116 is equal to or greater than the sum of the thickness of the upper wall 85 and the thickness of the adhesive A2. On the other hand, the thick-walled portion 115 and the thin-walled portion 117 are separated from the protective member 19 in a direction perpendicular to the Z direction (+Z direction). In other words, the thick-walled portion 115 and the thin-walled portion 117 do not overlap with the protective member 19.

[0120] The inclined surface 61c of the center portion 61 of the inner cover 16 overlaps the thin portion 117 in the +Z direction. On the other hand, the thick portion 115 and the thin portion 116 are spaced apart from the inclined surface 61c in a direction perpendicular to the Z direction (+Z direction).

[0121] The viscoelastic body 112 is interposed between the inner surface 115b of the thick wall portion 115 and the mounting surface 61b of the central portion 61 of the inner cover 16. Furthermore, the viscoelastic body 112 is interposed between the inner surface 116b of the thin wall portion 116 and the mounting surface 61b of the central portion 61 of the inner cover 16. That is, both the thick wall portion 115 and the thin wall portion 116 are mounted on the mounting surface 61b via the viscoelastic body 112.

[0122] Adhesive A4 is attached to the inner surface 71b of the central portion 71 and the inner surface 72b of the peripheral portion 72 of the outer cover 17. Adhesive A4 is, for example, a double-sided tape. Adhesive A4 attaches the inner surface 71b of the central portion 71 to the upper surface 115a of the thick portion 115 and the upper surface 117a of the thin portion 117. Furthermore, adhesive A4 attaches the inner surface 72b of the peripheral portion 72 to the upper surface 116a of the thin portion 116.

[0123] The magnetic disk 31 overlaps the constraining layer 111 in the +Z direction. On the other hand, the spindle motor 32 is separated from the constraining layer 111 in a direction intersecting the Z direction (+Z direction). In addition, a part of the magnetic disk 31 may not overlap the constraining layer 111.

[0124] The HDD 10 of this embodiment is mounted on, for example, a server rack of a server. The server rack, for example, is equipped with a plurality of HDDs 10 and cooling fans. Vibration generated by other devices such as the cooling fan may be transmitted to the HDD 10 .

[0125] When vibration is input to the HDD 10, the housing 11 vibrates, and the vibration of the housing 11 is transmitted to the damping members 91 and 92. As a result, the constrained layers 101 and 111 vibrate relative to the housing 11. The viscoelastic bodies 102 and 112 deform between the constrained layers 101 and 111 and the inner cover 16, and convert the energy of the vibration into heat. As a result, the damping members 91 and 92 attenuate the vibration of the housing 11.

[0126] The constraining layers 101 and 111 are attached to the outer cover 17 by adhesives A3 and A4. However, the outer cover 17 is thin and has lower rigidity than the constraining layers 101 and 111. Therefore, the outer cover 17 deforms following the vibration of the constraining layers 101 and 111. In other words, the constraining layers 101 and 111 can vibrate relative to the housing 11 even if attached to the outer cover 17.

[0127] The damper 91 attenuates the vibration input to the housing 11 in the vicinity of the VCM 34 . Therefore, the damper 91 can attenuate the vibration input to the HSA 33 in the vicinity of the VCM 34 .

[0128] The damper 92 attenuates the vibration input to the housing 11 in the vicinity of the magnetic disk 31. Therefore, the damper 92 can attenuate the vibration input to the HSA 33 in the vicinity of the magnetic disk 31.

[0129] Since the vibration of the HSA 33 is attenuated by the damping members 91 and 92, the magnetic head 45 can be positioned with good accuracy even if the recording density is high in the HDD 10. That is, the HDD 10 can increase the recording density.

[0130] In the technical field of HDD, the Small Form Factor Committee has established, for example, SFF-8300 as an external form factor specification for a 3.5-inch hard disk drive. SFF-8300 sets a plurality of maximum dimensions (hereinafter referred to as specified dimensions) for the dimensions of a HDD in the Z direction.

[0131] In a HDD filled with helium, helium leakage is suppressed by, for example, welding a cover to a base. The protective member protects the portion formed by welding the base and the cover. However, when the protective member is attached to a flat cover, the HDD exceeds a specified size or the space inside the HDD becomes smaller.

[0132] In this embodiment, the upper walls 81 and 85 of the protectors 18 and 19 are arranged in the recesses 75 and 76. Thereby, the dimension of the HDD 10 in the Z direction can be made to comply with the predetermined dimension, and the storage space S in the Z direction can be made larger.

[0133] On the other hand, by providing the recesses 75 and 76 in the outer cover 17, a narrow gap GN is provided in the gap G between the inner cover 16 and the outer cover 17. In addition, if the number of magnetic disks 31 is large, the VCM 34 is enlarged in the Z direction. As the VCM 34 is enlarged, the gap GN is narrower at the position overlapping the VCM 34.

[0134] A damping member with a thick constrained layer is difficult to arrange in a small gap GN. However, the constrained layers 101 and 111 of this embodiment have thin-walled portions 106 and 116 that can be arranged in the gap GN. Therefore, the constrained layers 101 and 111 can also be arranged in the gap GN and can be formed wider along the inner cover 16 .

[0135] Generally, in order to effectively damp vibrations of the damping member, the constrained layer is set to a predetermined mass. If the constrained layer is thin and light, the vibration damping effect of the damping member may be reduced. However, the constrained layers 101 and 111 of the present embodiment have thick wall portions 105 and 115 at the wide gap GW, thereby being able to obtain a predetermined mass.

[0136] As can be seen from the above, the HDD 10 of this embodiment can set the storage space S larger in the Z direction under the size restriction of SFF-8300, and arrange the constraining layers 101 and 111 of a size that can effectively attenuate vibration in the gap G. By setting the storage space S larger, the HDD 10 can, for example, increase the number of magnetic disks 31 and thus increase the storage capacity.

[0137] In the HDD 10 of the first embodiment described above, the base 15 has a bottom surface 21a, a side wall 22, and an end surface 22a. The bottom surface 21a faces the magnetic disk 31. The side wall 22 protrudes from the bottom surface 21a in the +Z direction and surrounds the magnetic disk 31. The end surface 22a is provided at the end of the side wall 22 in the +Z direction. A storage space S for arranging the magnetic disk 31 is provided inside the bottom surface 21a and the side wall 22. The inner cover 16 is mounted on the base 15 in a manner of closing the storage space S. The outer cover 17 covers the inner cover 16 and is supported by the end surface 22a and is coupled to the base 15. The damping member 91 has a constraining layer 101 located between the inner cover 16 and the outer cover 17, and a viscoelastic body 102 interposed between the inner cover 16 and the constraining layer 101. The constraining layer 101 has a thin-walled portion 106 and a thick-walled portion 105 connected to the thin-walled portion 106. The thin-walled portion 106 is provided along the end surface 22 a . The thick-walled portion 105 is thicker than the thin-walled portion 106 in the +Z direction.

[0138] As described above, the thin-walled portion 106 is provided along the end surface 22a. The end surface 22a is formed into a frame shape because it is provided at the end of the side wall 22 surrounding the magnetic disk 31. That is, the thin-walled portion 106 is located near the outer edges of the base 15, the inner cover 16, and the outer cover 17. Generally speaking, the gap G (gap GN) between the outer edge of the inner cover 16 and the outer edge of the outer cover 17 is narrow. For example, a protective member 18 covering the weld B formed by the combination of the base 15 and the outer cover 17 is installed on the outer edge of the outer cover 17. In this case, the peripheral edge portion 72 of the outer edge of the outer cover 17 is bent in a manner close to the inner cover 16 in such a manner that the size of the HDD 10 in the +Z direction is set within a prescribed range defined by SFF-8300, and a recess 75 for the protective member 18 to be embedded is provided. In another example, in order to suppress the outer edge of the outer cover 17 located at the corner of the HDD 10 from colliding with other components when the HDD 10 is mounted on the server rack, the outer edge of the outer cover 17 is bent so as to approach the inner cover 16, so that the outer edge of the outer cover 17 is recessed. In this embodiment, since the thin-walled portion 106 in the constraining layer 101 is arranged near the outer edges of the inner cover 16 and the outer cover 17, the thin-walled portion 106 can be arranged in the narrow gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17. That is, the constraining layer 101 can be provided not only in the wide gap GW, but also in the narrow gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17, and can be formed wider. On the other hand, the constraining layer 101 can be provided with a thick-walled portion 105 in the wide gap G (gap GW) between the inner cover 16 and the outer cover 17 away from the outer edge. As described above, the constraining layer 101 can be installed in the inner cover 16 in a larger size under the restrictions on the size of the HDD 10 under various conditions. Generally, if the constrained layer 101 is heavy, the damper 91 can effectively damp vibration. The constrained layer 101 of this embodiment is large in width and thickness and thus heavy. Therefore, the HDD 10 of this embodiment can reduce vibration and noise through the damper 91.

[0139] In other words, the base 15 has a bottom surface 21a and a side wall 22. The bottom surface 21a faces the magnetic disk 31. The side wall 22 protrudes from the bottom surface 21a in the +Z direction and surrounds the magnetic disk 31. A storage space S for arranging the magnetic disk 31 is provided inside the bottom surface 21a and the side wall 22. The inner cover 16 is mounted on the base 15 in such a manner as to block the storage space S. The outer cover 17 covers the inner cover 16 and is coupled to the base 15. The damping member 91 has a constraining layer 101 located between the inner cover 16 and the outer cover 17, and a viscoelastic body 102 interposed between the inner cover 16 and the constraining layer 101. The constraining layer 101 has a thick wall portion 105 and a thin wall portion 106 connected to the thick wall portion 105. The thin wall portion 106 is located between the weld B formed by coupling the base 15 and the outer cover 17 and the thick wall portion 105, and is thinner than the thick wall portion 105 in the +Z direction.

[0140] As described above, the thin-walled portion 106 is located between the weld B and the thick-walled portion 105. That is, the thin-walled portion 106 is located near the outer edges of the base 15, the inner cover 16, and the outer cover 17. Generally, the gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17 is narrow. In this embodiment, since the thin-walled portion 106 in the constraining layer 101 is arranged near the outer edges of the inner cover 16 and the outer cover 17, the thin-walled portion 106 can be arranged in the narrow gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17. That is, the constraining layer 101 can be provided not only in the wide gap GW, but also in the narrow gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17, and can be formed wider. On the other hand, the constraining layer 101 can provide the thick-walled portion 105 in the wide gap GW between the inner cover 16 and the outer cover 17 away from the outer edge. As described above, the constraining layer 101 can be mounted on the inner cover 16 in a larger size under the restrictions on the size of the HDD 10 under various conditions. In addition, the constrained layer 101 of the present embodiment is increased in width and thickness and thus becomes heavy. Therefore, the HDD 10 of the present embodiment can reduce vibration and noise by the damper 91 .

[0141] The outer cover 17 is coupled to the end surface 22a. Therefore, the gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17 is narrowed. However, in the present embodiment, the thin-walled portion 106 in the constraint layer 101 is arranged near the outer edges of the inner cover 16 and the outer cover 17, so the thin-walled portion 106 can be arranged in the narrow gap GN between the outer edge of the inner cover 16 and the outer edge of the outer cover 17. Therefore, the HDD 10 of the present embodiment can enlarge the constraint layer 101 under the limitation of the size of the HDD 10 under various conditions, and can reduce vibration and noise through the damping member 91.

[0142] The storage space S is filled with a gas different from air. For example, the storage space S is filled with helium. In this case, the vibration caused by the internal components of the HDD 10 is unlikely to affect the positioning of the magnetic head 45, for example. On the other hand, the vibration input from the outside to the HDD 10 may affect the positioning of the magnetic head 45. However, the HDD 10 of this embodiment can attenuate the vibration input from the outside by the damping member 91, so the magnetic head 45 can be positioned more accurately.

[0143] The protective member 18 covers the weld B formed by the outer cover 17 being joined to the base 15. The thin-walled portion 106 overlaps with the protective member 18 in the +Z direction. The thick-walled portion 105 is separated from the protective member 18 in the direction orthogonal to the +Z direction. The protective member 18 also overlaps with the outer cover 17. Therefore, in a manner that the size of the HDD 10 in the +Z direction is set within a predetermined range defined in SFF-8300, the outer edge of the outer cover 17 is bent so as to approach the inner cover 16, and a recess 75 is provided for the protective member 18 to be embedded. As a result, at a position separated from the protective member 18, for example, the gap GW between the inner cover 16 and the outer cover 17 can be enlarged or the storage space S can be enlarged. On the other hand, at a position overlapping with the protective member 18, the gap GN between the inner cover 16 and the outer cover 17 is narrowed. However, the thin-walled portion 106 is arranged in the narrow gap GN between the inner cover 16 and the outer cover 17, so the constraining layer 101 can be formed more widely. In addition, since the thick wall portion 105 is separated from the protector 18, it can be disposed in the wide gap GW between the inner cover 16 and the outer cover 17. Therefore, the HDD 10 of this embodiment can enlarge the constraining layer 101 under the constraints imposed on the size of the HDD 10 by various conditions, and the damping member 91 can reduce vibration and noise.

[0144] The protective member 18 has an upper wall 81. The upper wall 81 covers the outer cover 17 and is attached to the outer cover 17 by the adhesive A1. The thin-walled portion 106 overlaps with the upper wall 81 in the +Z direction. In the +Z direction, the difference L3 between the thickness of the thick-walled portion 105 and the thickness of the thin-walled portion 106 is equal to or greater than the sum L2 of the thickness of the upper wall 81 and the thickness of the adhesive A1. The outer edge of the outer cover 17 is bent, for example, along the step between the thick-walled portion 105 and the thin-walled portion 106 so as to approach the inner cover 16, and a recess 75 is provided in which the upper wall 81 of the protective member 18 is embedded. In this case, the depth L1 of the recess 75 in the +Z direction is generally substantially equal to the difference L3 between the thickness of the thick-walled portion 105 and the thickness of the thin-walled portion 106. Therefore, the sum L2 of the thickness of the upper wall 81 and the adhesive A1 embedded in the recess 75 is less than the depth L1 of the recess 75. Therefore, the HDD 10 of the present embodiment can suppress the size of the HDD 10 in the +Z direction from exceeding a predetermined value defined in SFF-8300 due to the protection member 18 .

[0145] The protective member 18 has an upper wall 81 that covers the outer cover 17 and is attached to the outer cover 17 by the adhesive A1. The thin-walled portion 106 overlaps with the upper wall 81 in the +Z direction. The outer cover 17 has an outer surface 71a that is set at the end of the outer cover 17 in the +Z direction. The outer cover 17 is provided with a recessed portion 75 that is recessed from the outer surface 71a and for which the upper wall 81 is arranged. In the +Z direction, the depth L1 of the recessed portion 75 is equal to or greater than the sum L2 of the thickness of the upper wall 81 and the thickness of the adhesive A1. Therefore, the HDD 10 of the present embodiment can suppress the situation in which the size of the HDD 10 in the +Z direction exceeds a specified value set by SFF-8300 due to the protective member 18.

[0146] The protector 18 covers the end of the outer cover 17 in the -Y direction orthogonal to the +Z direction. The thin-walled portion 106 includes a first thin-walled portion 107 and a second thin-walled portion 108. The first thin-walled portion 107 is located between the end of the inner cover 16 in the -Y direction and the thick-walled portion 105. The second thin-walled portion 108 is located between the end of the inner cover 16 in the -X direction orthogonal to the +Z direction and to the -Y direction and the thick-walled portion 105. The first thin-walled portion 107 overlaps with the protector 18 in the +Z direction. The second thin-walled portion 108 is separated from the protector 18 in the direction orthogonal to the +Z direction. The length (width) of the first thin-walled portion 107 in the -Y direction is longer than the length (width) of the second thin-walled portion 108 in the -X direction. That is, the width of the first thin-walled portion 107 overlapping with the protector 18 is wide, and the width of the second thin-walled portion 108 not overlapping with the protector 18 is narrow. Thus, the constrained layer 101 can minimize the width of the second thin portion 108 in the −X direction and maximize the width of the thick portion 105 in the −X direction, for example. Therefore, the constrained layer 101 can be increased in thickness.

[0147] The magnetic head 45 reads and writes information to the magnetic disk 31. The magnetic head 45 is mounted on the suspension 46. The suspension 46 is mounted on the slide 35. The VCM 34 has a magnet 52 and is configured to rotate the slide 35. The constraining layer 101 is a magnetic body. The magnet 52 overlaps with the constraining layer 101 in the +Z direction. Thus, the constraining layer 101 can shield (seal) the magnetic flux generated from the magnet 52, and can suppress the magnetic flux leaking from the HDD 10 from affecting other HDDs in the server rack, for example.

[0148] The constrained layer 101 is made of ferromagnetic stainless steel. Therefore, the rigidity and weight of the thin-walled portion 106 of the constrained layer 101 are relatively large. Therefore, the damping member 91 can effectively attenuate vibration.

[0149] The magnet 52 has two magnetic poles 52a, 52b and a boundary 52c between the two magnetic poles 52a, 52b. The boundary 52c overlaps with the thick wall portion 105 in the +Z direction. At the boundary 52c between the two magnetic poles 52a, 52b, the magnetic flux has a specific property compared to each magnetic pole 52a, 52b. Therefore, around the boundary 52c, the leakage of the magnetic flux sometimes becomes larger. However, the thick wall portion 105 can shield the magnetic flux more effectively than the thin wall portion 106. Therefore, the HDD 10 of this embodiment can more reliably block the magnetic flux leaking from the periphery of the boundary 52c.

[0150] The magnet 52 overlaps the constrained layer 101 in the +Z direction as a whole. Thus, the constrained layer 101 can more reliably shield the magnetic flux generated by the magnet 52 and suppress the leakage of the magnetic flux from the HDD 10 .

[0151] The base 15 and the outer cover 17 are made of aluminum alloy, and the inner cover 16 is made of non-magnetic stainless steel, and both are non-magnetic bodies.

[0152] Generally speaking, the linear expansion coefficient of non-magnetic stainless steel is closer to that of aluminum alloy than that of magnetic stainless steel. By using non-magnetic stainless steel for the inner cover 16, the housing 11 is composed of the base 15, the inner cover 16, and the outer cover 17, which have similar linear expansion coefficients, and the divergence of the thermal expansion / contraction between the components of the housing 11 when the temperature changes can be suppressed. As a result, the HDD 10 can suppress the warping of the housing 11 caused by the difference in the thermal expansion / contraction between the base 15 and the inner cover 16, for example.

[0153] The viscoelastic body 102 is interposed between the thin wall portion 106 and the inner cover 16 and between the thick wall portion 105 and the inner cover 16. That is, the viscoelastic body 102 is provided in a wider range between the constraining layer 101 and the inner cover 16. Thus, the damping member 91 can effectively attenuate vibration.

[0154] The magnetic disk 31 overlaps with the constraining layer 111 of the damping member 92 in the +Z direction. The portion overlapping with the magnetic disk 31 in the gap G between the inner cover 16 and the outer cover 17 is wider than the portion overlapping with the VCM 34, for example. Therefore, the constraining layer 111 of the present embodiment is enlarged in width and thickness and thus becomes heavier. Therefore, the HDD 10 of the present embodiment can reduce vibration and noise by the damping member 92.

[0155] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of the invention, and are included in the invention described in the claims and their equivalents.

Claims

1. A disk device comprising: disk; A base body having a bottom surface facing the magnetic disk, a side wall protruding from the bottom surface in a first direction and surrounding the magnetic disk, and a supporting surface provided at an end of the side wall in the first direction, wherein a storage space for arranging the magnetic disk is provided inside the bottom surface and the side wall; a first cover mounted on the base body in a manner of blocking the storage space; a second cover covering the first cover and supported by the support surface and coupled to the base; as well as a damping member having a constraining layer located between the first cover and the second cover, and a viscoelastic body interposed between the first cover and the constraining layer; The constrained layer includes a thin-walled portion provided along the support surface and a thick-walled portion connected to the thin-walled portion and thicker than the thin-walled portion in the first direction.

2. The disk device according to claim 1, The second cover is coupled to the support surface.

3. A disk device comprising: disk; A base body having a bottom surface facing the magnetic disk and a side wall protruding from the bottom surface in a first direction and surrounding the magnetic disk, wherein a storage space for arranging the magnetic disk is provided inside the bottom surface and the side wall; a first cover mounted on the base body in a manner of blocking the storage space; a second cover covering the first cover and coupled to the base; as well as a damping member having a constraining layer located between the first cover and the second cover, and a viscoelastic body interposed between the first cover and the constraining layer; The constraining layer has a thick portion and a thin portion, wherein the thin portion is located between the thick portion and a portion formed by combining the base and the second cover, is connected to the thick portion, and is thinner than the thick portion in the first direction.

4. The disk device according to claim 1 or 3, The storage space is filled with a gas different from air.

5. The disk device according to claim 1 or 3, The disk device further includes a third cover covering a portion formed by bonding the second cover to the base; The thin-walled portion overlaps with the third cover in the first direction; The thick portion is spaced apart from the third cover in a direction perpendicular to the first direction.

6. The disk device according to claim 5, The disk device further comprises an adhesive; The third cover has a covering wall covering the second cover and mounted on the second cover by the adhesive; The thin-walled portion overlaps with the covering wall in the first direction; In the first direction, a difference between a thickness of the thick wall portion and a thickness of the thin wall portion is equal to or greater than a sum of a thickness of the covering wall and a thickness of the adhesive.

7. The disk device according to claim 5, The disk device further comprises an adhesive; The third cover has a covering wall covering the second cover and being attached to the second cover by the adhesive; The thin-walled portion overlaps with the covering wall in the first direction; The second cover has an outer surface provided at an end portion of the second cover in the first direction, and is provided with a recessed portion recessed from the outer surface and in which the covering wall is arranged; In the first direction, the depth of the recess is equal to or greater than the sum of the thickness of the covering wall and the thickness of the adhesive.

8. The disk device according to claim 5, The third cover covers an end portion of the second cover in a second direction orthogonal to the first direction; The thin-walled portion includes a first thin-walled portion located between an end portion of the first cover and the thick-walled portion in the second direction, and a second thin-walled portion located between an end portion of the first cover and the thick-walled portion in a third direction that is orthogonal to the first direction and to the second direction, and the first thin-walled portion overlaps with the third cover in the first direction; The second thin-walled portion is spaced apart from the third cover in a direction perpendicular to the first direction; A length of the first thin-walled portion in the second direction is longer than a length of the second thin-walled portion in the third direction.

9. The disk device according to claim 1 or 3, The disk device further comprises: A magnetic head for reading and writing information on the magnetic disk; a suspension, on which the magnetic head is mounted; a carriage on which the suspension is mounted; and an actuator having a magnet and configured to rotate the carriage; The constrained layer is a magnetic body; The magnet overlaps the confinement layer in the first direction.

10. The disk device according to claim 9, The constraining layer is made of ferromagnetic stainless steel.

11. The disk device according to claim 9, The magnet has two poles and a boundary between the two poles; The boundary overlaps the thick portion in the first direction.

12. The disk device according to claim 9, The entirety of the magnet overlaps with the constrained layer in the first direction.

13. The disk device according to claim 9, The base and the second cover are non-magnetic bodies.

14. The disk device according to claim 9, The first cover is a non-magnetic body.

15. The disk device according to claim 1 or 3, The viscoelastic body is interposed between the thin-walled portion and the first cover and between the thick-walled portion and the first cover.

16. The disk device according to claim 1 or 3, The magnetic disk overlaps the constrained layer in the first direction.

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