disc device

Abstract

The present disclosure provides a disk device capable of increasing storage capacity per unit volume. A disk device of one embodiment includes a plurality of disks, a spindle motor, and a housing. The disks have recording surfaces and are arranged at intervals from each other in an axial direction intersecting the recording surfaces. The spindle motor holds the disks so that the disks rotate around a first rotation axis extending in the axial direction. The housing has a first wall in which the spindle motor is installed and which is separated from the disks in the axial direction, a second wall provided to an outer surface of the first wall and protruding from the first wall and surrounding the disks. A maximum distance between the inner surface and the outer surface in the axial direction is 1.5% or more and 8% or less of a maximum dimension of the housing in the axial direction.

Description

[0001] This application claims priority to Japanese Patent Application No. 2022-044186 (filed on March 18, 2022). This application incorporates the entire contents of that basic application by reference. Technical Field

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

[0003] Disk devices such as hard disk drives have multiple disks. Generally, the storage capacity of a disk device increases as the number of disks it contains increases.

[0004] To achieve the desired storage capacity, multiple disk units are sometimes prepared. In this case, the larger the storage capacity per unit volume of the disk unit, the less likely the number of disk units need to be prepared. Summary of the Invention

[0005] One example of the problem to be solved by the present invention is to provide a disk device that can increase the storage capacity per unit volume.

[0006] One embodiment of the disk assembly includes a plurality of disks, a spindle motor, and a housing. The plurality of disks each have a recording surface and are arranged at intervals from each other in an axial direction intersecting the recording surfaces. The spindle motor is configured to hold the plurality of disks and rotate them about a first rotation axis extending in the axial direction. The housing has a first wall for mounting the spindle motor and separated from the plurality of disks in the axial direction, an inner surface disposed on the first wall and facing the recording surface, an outer surface disposed on the first wall and located opposite the inner surface, and a second wall protruding from the first wall and surrounding the plurality of disks in a direction orthogonal to the axial direction. The housing accommodates the plurality of disks. The maximum distance between the inner surface and the outer surface in the axial direction is more than 1.5% and less than 8% of the maximum dimension of the housing in the axial direction. Attached Figure Description

[0007] Figure 1 This is an illustrative top view showing a hard disk drive (HDD) according to the first embodiment.

[0008] Figure 2 The HDD of the first embodiment is along Figure 1 An illustrative sectional view shown along line F2-F2.

[0009] Figure 3 This is an exemplary perspective view showing the ramp loading mechanism of the first embodiment.

[0010] Figure 4This is an illustrative cross-sectional view that schematically shows a portion of the HDD of the first embodiment.

[0011] Figure 5 This is an illustrative cross-sectional view that schematically shows another part of the HDD of the first embodiment.

[0012] Figure 6 This is an illustrative cross-sectional view that schematically shows a portion of the HDD of the second embodiment.

[0013] Figure 7 This is an illustrative cross-sectional view showing a portion of the HDD according to the third embodiment.

[0014] Label Explanation

[0015] 10…Hard disk drive (HDD), 11…Casing, 11a…End, 12…Disk, 12a…Recording surface, 13…Spindle motor, 14…Head, 17…Ramp loading mechanism, 22…Cover, 25…Bottom wall, 25a…Inner surface, 25b…Outer surface, 26…Side wall, 26a…End face, 26d…Parting line 26e…first inclined plane, 26g…first shroud, 26h…second shroud, 26i…step, 31…stator, 32…rotor, 33…bearing, 34…spacer, 42…coil, 44…shaft, 55…carriage, 56…suspension, 62…arm, 71…first disk, 72…second disk, 75…first arm, 76…second arm, 77…first spacer, 78…second spacer, 126…sidewall, 126f…second inclined plane, Ax1…first rotating shaft, Ax2…second rotating shaft, Dd, Ds, Dd1, Dd2, Di1, Di2…diameter, Db, Dh…thickness, Dc…dimension, Dp…distance, Ta1, Ta2, Td1, Td2, Ts1, Ts2…dimension, θ1, θ2…angle. Detailed Implementation

[0016] (First Embodiment)

[0017] Hereinafter, regarding the first embodiment, refer to Figures 1-5 This will be explained in more detail. Furthermore, in this specification, the constituent elements of an embodiment and their descriptions are sometimes described using multiple expressions. The constituent elements and their descriptions are merely examples and are not limited to the expressions in this specification. Constituent elements can also be identified by names different from those used in this specification. Additionally, constituent elements can also be described using expressions different from those used in this specification.

[0018] Figure 1This is an exemplary top view showing the hard disk drive (HDD) 10 of the first embodiment. The HDD 10 is an example of a disk device and can also be referred to as an electronic device, storage device, external storage device, or disk device.

[0019] As shown in the accompanying figures, the X-axis, Y-axis, and Z-axis are defined in this specification for convenience. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis is set along the width of the HDD10. The Y-axis is set along the length of the HDD10. The Z-axis is set along the thickness of the HDD10.

[0020] Furthermore, in this specification, the X, Y, and Z directions are defined. The X direction is the direction along the X-axis, including the +X direction indicated by the arrow on the X-axis and the opposite direction of the arrow on the X-axis, i.e., the -X direction. The Y direction is the direction along the Y-axis, including the +Y direction indicated by the arrow on the Y-axis and the opposite direction of the arrow on the Y-axis, i.e., the -Y direction. The Z direction is the direction along the Z-axis, including the +Z direction indicated by the arrow on the Z-axis and the opposite direction of the arrow on the Z-axis, i.e., the -Z direction.

[0021] Figure 2 The HDD10 of the first embodiment is along Figure 1 An illustrative cross-sectional view shown along line F2-F2. The HDD10 has... Figure 1 The components shown include: housing 11, multiple disks 12, spindle motor 13, multiple read / write heads 14, multiple actuator assemblies 15, multiple voice coil motors (VCMs) 16, multiple ramp loading mechanisms 17, flexible printed circuit boards (FPCs) 18, and... Figure 2 The printed circuit board (PCB) 19 is shown. The disk 12 can also be referred to as a platter or medium. The read / write head 14 can also be referred to as a slider. The ramp loading mechanism 17 is an example of a ramp.

[0022] An inner chamber S is provided inside the housing 11. The housing 11 houses the disk 12, spindle motor 13, read / write head 14, actuator assembly 15, VCM 16, ramp loading mechanism 17, and FPC 18 within the inner chamber S.

[0023] like Figure 2 As shown, the housing 11 has a base 21 and a cover 22. However, the housing 11 is not limited to this example. Additionally, Figure 1 For illustrative purposes, the housing 11 is shown with the cover 22 omitted.

[0024] The substrate 21 is made of a metallic material such as aluminum alloy and is formed into a generally rectangular box shape that is open in the +Z direction. The substrate 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is an example of the first wall. The side wall 26 is an example of the second wall.

[0025] The bottom wall 25 is formed as a generally rectangular (quadrilateral) plate extending along the XY plane. The side wall 26 protrudes from the edge of the bottom wall 25 in a generally +Z direction, forming a generally rectangular frame. The bottom wall 25 and the side wall 26 are integrally formed. The bottom wall 25 has an inner surface 25a and an outer surface 25b.

[0026] The inner surface 25a is the inner surface of the base 21 provided on the bottom wall 25. The inner surface 25a as a whole faces approximately in the +Z direction. In addition, the inner surface 25a may also be provided with a plurality of protrusions and recesses facing in a direction different from the +Z direction.

[0027] The outer surface 25b is the outer surface of the base 21 provided on the bottom wall 25. That is, the outer surface 25b is exposed on the outside of the housing 11. The outer surface 25b is located on the opposite side of the inner surface 25a. The outer surface 25b as a whole faces approximately in the -Z direction. In addition, the outer surface 25b may also be provided with a plurality of protrusions and recesses facing a direction different from the -Z direction.

[0028] An end 11a of the housing 11 in the -Z direction is provided on the outer surface 25b. End 11a is an example of a first end. End 11a is also the end of the HDD 10 in the -Z direction. However, end 11a is not limited to this example.

[0029] The sidewall 26 has an end face 26a. The end face 26a is an example of a second end. The end face 26a is located at the end of the sidewall 26 in the +Z direction. The end face 26a is located on the opposite side of the outer surface 25b (end 11a) of the bottom wall 25 in the substrate 21. The end face 26a is formed to be generally flat and faces generally in the +Z direction.

[0030] The cover 22 is made of a metal material such as aluminum alloy. The cover 22 is fixed to the end face 26a of the side wall 26 by welding, for example. The cover 22 may also have an inner cover fixed to the side wall 26 by screws and an outer cover covering the inner cover and fixed to the end face 26a by welding.

[0031] The inner chamber S is formed, for example, by a bottom wall 25, side walls 26, and a cover 22 (defined, defined). The inner chamber S is airtight. Furthermore, minute gas movement is also possible between the inner chamber S and the outside of the housing 11.

[0032] The inner chamber S is filled with a gas different from air. For example, a low-density gas with a lower density than air, or an inert gas with low reactivity, may be filled in the inner chamber S. In this embodiment, helium is filled in the inner chamber S. Alternatively, other fluids may be used to fill the inner chamber S.

[0033] Multiple disks 12 are formed in a disk shape extending along the XY plane. In this embodiment, the diameter Dd of each of the multiple disks 12 is, for example, about 3.5 inches, specifically set to be more than 80 mm and less than 100 mm. Furthermore, the diameter Dd of the disks 12 is not limited to this example. Each of the multiple disks 12 has at least one recording surface 12a and an outer edge 12b.

[0034] Recording surfaces 12a are disposed on at least one of the upper and lower surfaces of the disk 12. In other words, the plurality of recording surfaces 12a are either surfaces of the disk 12 facing approximately the +Z direction or surfaces of the disk 12 facing approximately the -Z direction.

[0035] The recording surface 12a is a generally flat surface extending along the XY plane. The magnetic recording layer of the disk 12 is disposed on the recording surface 12a. Alternatively, a portion of the recording surface 12a may not have a magnetic recording layer. The outer edge 12b is the outer peripheral surface of the disk 12.

[0036] Multiple disks 12 are arranged with intervals between them in the Z direction. The Z direction is the direction that intersects the recording surface 12a and is an example of an axial direction. The recording surface 12a of one of two adjacent disks 12 facing the +Z direction and the recording surface 12a of the other disk 12 facing the -Z direction are spaced apart and face each other.

[0037] The number of disks (12) is, for example, 20 or more. Figure 2 In this example, HDD10 has 20 disks 12. Furthermore, the number of disks 12 is not limited to this example.

[0038] Multiple disks 12 are located between a cover 22 and a bottom wall 25 in the Z direction. The cover 22 and the bottom wall 25 are separated from the multiple disks 12 in the Z direction. The recording surfaces 12a of the multiple disks 12 facing the Z direction and the inner surface 25a of the bottom wall 25 face each other with a gap between them.

[0039] Sidewall 26 surrounds a plurality of disks 12 in a direction orthogonal to the Z direction. Sidewall 26 is separated from the plurality of disks 12. Sidewall 26 has a shield 26b. Shield 26b is a generally cylindrical curved surface extending along the outer edge 12b of disk 12 and facing the outer edge 12b with a generally constant gap.

[0040] Spindle motor 13 holds multiple disks 12. Spindle motor 13 causes the multiple disks 12 to rotate about a first rotation axis Ax1. The first rotation axis Ax1 is an imaginary axis extending in the Z direction (+Z direction and -Z direction).

[0041] In this specification, axial, radial, and circumferential directions are defined. The axial direction is the direction along the first rotation axis Ax1, including both directions along the first rotation axis Ax1 and another direction. The axial direction is the same as the Z direction. The radial direction is the direction orthogonal to the first rotation axis Ax1, including multiple directions orthogonal to the first rotation axis Ax1. The circumferential direction is the direction of rotation about the first rotation axis Ax1, including both clockwise and counterclockwise directions about the first rotation axis Ax1.

[0042] The first rotation axis Ax1 is the rotation center of the spindle motor 13, and also the central axis of the disk 12 and the spindle motor 13. Alternatively, the central axis of the disk 12 and the central axis of the spindle motor 13 may differ from the rotation center of the spindle motor 13. The spindle motor 13 has a stator 31, a rotor 32, bearings 33, and multiple spacers 34.

[0043] The stator 31 is mounted on the bottom wall 25. The stator 31 may include, for example, a sleeve 41, a plurality of coils 42, a plurality of iron cores 43, and a shaft 44. However, the stator 31 is not limited to this example.

[0044] The sleeve 41 is formed in a generally cylindrical shape that surrounds the first rotation axis Ax1 and extends in the Z direction. The sleeve 41 protrudes from the inner surface 25a of the bottom wall 25 in the +Z direction. Alternatively, the sleeve 41 may be a component different from the bottom wall 25.

[0045] Multiple coils 42 are each wound around a corresponding iron core 43. The coils 42 and the iron cores 43 form magnetic poles. The multiple coils 42 and the multiple iron cores 43 are located radially outside the sleeve 41 and are arranged at approximately equal intervals in the circumferential direction. In other words, the coils 42 surround the first rotation axis Ax1.

[0046] The shaft 44 is formed into a generally cylindrical shape extending in the Z direction along the first rotation axis Ax1. The shaft 44 is embedded inside the sleeve 41 and mounted on the housing 11. In this embodiment, the diameter Ds of the shaft 44 is set to be 5 mm or more and 10 mm or less. However, the diameter Ds of the shaft 44 is not limited to this example.

[0047] The rotor 32 rotates about a first rotation axis Ax1 relative to the housing 11 and the stator 31. The rotor 32 has a hub 45, a magnet 46, and a clamping member 47. However, the rotor 32 is not limited to this example.

[0048] The hub 45 is formed in a generally cylindrical shape that surrounds the first rotating shaft Ax1 and extends in the Z direction. The hub 45 has an outer surface 45a, a first inner surface 45b, a second inner surface 45c and a flange 45d.

[0049] The outer surface 45a is formed into a generally cylindrical shape facing radially outward. The first inner surface 45b and the second inner surface 45c are located opposite the outer surface 45a and are formed into a generally cylindrical shape facing radially inward. The first inner surface 45b surrounds a plurality of coils 42 and a plurality of iron cores 43. The second inner surface 45c is further separated from the bottom wall 25 than the first inner surface 45b. The second inner surface 45c faces the shaft 44. A flange 45d protrudes radially outward from the end of the outer surface 45a in the -Z direction.

[0050] Magnet 46 is disposed together with the yoke on the first inner surface 45b. Magnet 46 is located radially outside the plurality of coils 42 and the plurality of iron cores 43. The magnetic poles formed by the plurality of coils 42 and the plurality of iron cores 43 face each other.

[0051] Clamping member 47 is mounted at the end of hub 45 in the +Z direction. Therefore, flange 45d and clamping member 47 are separated from each other in the Z direction. A portion of clamping member 47 protrudes radially outward from the outer surface 45a of hub 45. Clamping member 47 is subjected to force toward flange 45d, for example, by a spring.

[0052] Bearing 33 is, for example, a fluid bearing. Bearing 33 has, for example, two support members 48. The two support members 48 are mounted on shaft 44 at positions that are separated from each other in the Z direction.

[0053] Each of the two support members 48 has, for example, a generally conical support surface 48a. The support surface 48a faces the support surface 45e disposed on the hub 45. The support surface 45e of the hub 45 is a generally conical curved surface corresponding to the support surface 48a of the support member 48.

[0054] Lubricating oil is filled between the support surface 45e of the hub 45 and the support surface 48a of the support member 48. Therefore, the bearing 33 supports the rotor 32 via the lubricating oil in a manner that allows it to rotate about the first rotation axis Ax1. Grooves for generating dynamic pressure are provided on the support surface 45e. Furthermore, the bearing 33 is not limited to this example.

[0055] In the Z direction, bearing 33 is located between cover 22 and coil 42. Bearing 33 and coil 42 are arranged axially. Alternatively, bearing 33 and coil 42 may also be arranged radially, for example.

[0056] Multiple spacers 34 are each disposed between two adjacent disks of the plurality of disks 12. In other words, the plurality of disks 12 and the plurality of spacers 34 are disposed alternately in the Z direction. Thus, the plurality of spacers 34 maintain the spacing between the plurality of disks 12.

[0057] The outer surface 45a of the hub 45 is disposed inside the plurality of disks 12 and the plurality of spacers 34, facing the plurality of disks 12 and the plurality of spacers 34. The rotor 32 holds the plurality of disks 12 and the plurality of spacers 34 between the flange 45d of the hub 45 and the clamping member 47.

[0058] Figure 1 Each of the multiple read / write heads 14 recorded and reproduced information on a corresponding recording surface 12a of one of the multiple disks 12. In other words, the read / write heads 14 read and write information on the recording surface 12a of the disks 12. Each of the multiple read / write heads 14 is mounted on a corresponding actuator assembly of one of the multiple actuator assemblies 15.

[0059] Multiple actuator assemblies 15 are rotatably supported on a support shaft 51 disposed at a position detached from the disk 12. The support shaft 51 extends, for example, from the inner surface 25a of the bottom wall 25 in a generally +Z direction. The multiple actuator assemblies 15 are arranged in the Z direction.

[0060] Multiple actuator assemblies 15 can be independently referred to as actuator assemblies 15A and 15B. Actuator assembly 15A is closer to the bottom wall 25 than actuator assembly 15B. Actuator assembly 15B is closer to the cover 22 than actuator assembly 15A.

[0061] Multiple actuator assemblies 15A, 15B are capable of rotating independently about a second rotation axis Ax2 that is radially separated from the first rotation axis Ax1. That is, the HDD 10 has so-called multiple actuators. Alternatively, the HDD 10 may also have a single actuator assembly 15.

[0062] The second rotation axis Ax2 is an imaginary axis extending approximately in the Z direction (both the +Z and -Z directions). Therefore, the first rotation axis Ax1 and the second rotation axis Ax2 are arranged approximately parallel to each other. The second rotation axis Ax2 is, for example, the center of rotation of the actuator assembly 15, and also the central axis of the support shaft 51.

[0063] Each of the multiple VCMs 16 causes a corresponding actuator assembly of the multiple actuator assemblies 15A, 15B to rotate about the second rotation axis Ax2, positioning it in a desired position. Each of the multiple VCMs 16 is capable of causing the multiple actuator assemblies 15A, 15B to rotate at different angular velocities and in different directions.

[0064] Figure 3 This is an exemplary perspective view showing the ramp loading mechanism 17 of the first embodiment. The plurality of ramp loading mechanisms 17 are made of, for example, synthetic resin and arranged in the Z direction. In this embodiment, the number of the plurality of actuator assemblies 15, the number of the plurality of VCMs 16, and the number of the plurality of ramp loading mechanisms 17 are equal, but this is not limited to this example.

[0065] Multiple ramp loading mechanisms 17 are configured to be radially separated from the first rotation axis Ax1. Each of the multiple ramp loading mechanisms 17 holds its corresponding read / write head 14 in a position separated from the disk 12 as the corresponding read / write head 14 moves to the outermost periphery of the disk 12 due to the rotation of the actuator assembly 15 by the VCM 16.

[0066] Figure 1 The multiple actuator assemblies 15A and 15B shown each have a carriage 55 and multiple head suspension assemblies (suspensions) 56. That is, HDD10 has multiple carriages 55. The suspension 56 can also be referred to as a head universal joint assembly (HGA).

[0067] The carriage 55 is made of a metal material such as aluminum alloy. However, the material of the carriage 55 is not limited to this example. Each of the multiple carriages 55 has an actuator block 61 and multiple arms 62.

[0068] The actuator block 61 is rotatably supported on the support shaft 51, for example via a bearing. Thus, the multiple carriages 55 can rotate independently about the second rotation axis Ax2.

[0069] The actuator block 61 included in actuator assembly 15A can be referred to as actuator block 61A. The actuator block 61 included in actuator assembly 15B can be referred to as actuator block 61B. Actuator block 61A is located between bottom wall 25 and actuator block 61B. Actuator block 61B is located between cover 22 and actuator block 61A.

[0070] Multiple arms 62 protrude from actuator block 61 in a direction substantially orthogonal to the second rotation axis Ax2. The multiple arms 62 are arranged at intervals in the Z direction. Each arm 62 is formed as a plate capable of entering between adjacent disks 12. The multiple arms 62 extend substantially parallel to each other.

[0071] The corresponding voice coils of VCM16 are installed on the protrusions protruding from the actuator blocks 61A and 61B. VCM16 has a pair of yokes, a voice coil disposed between the yokes, and a magnet disposed on the yokes.

[0072] Multiple suspensions 56 are each mounted on the front end portion of the arm 62 of a corresponding carriage 55 and protrude from the arm 62. Thus, the multiple suspensions 56 are arranged at intervals in the Z direction. Each of the multiple suspensions 56 has a base plate 65, a load beam 66, and a flexible element 67.

[0073] The base plate 65 and the load-bearing beam 66 are made of, for example, stainless steel. Alternatively, the base plate 65 and the load-bearing beam 66 can be made of other materials, or even different materials.

[0074] The base plate 65 is plate-shaped and is mounted on the front end of the arm 62. The load beam 66 is mounted on the front end of the base plate 65 and protrudes from the base plate 65 in a direction approximately orthogonal to the second rotation axis Ax2.

[0075] The load beam 66 is thinner than the base plate 65 and is formed as a plate extending along the XY plane. That is, the load beam 66 is supported on the base plate 65 in a cantilever beam shape and can flex with one end of the base plate 65 as a fulcrum.

[0076] The flexible element 67 is formed in the form of an elongated strip. Furthermore, the shape of the flexible element 67 is not limited to this example. The flexible element 67 may be, for example, a laminate having a metal plate (lining layer) such as stainless steel, an insulating layer formed on the metal plate, a conductive layer formed on the insulating layer and having multiple wirings (wiring patterns), and a protective layer (insulating layer) covering the conductive layer.

[0077] Flexible member 67 is mounted on base plate 65 and load beam 66. A universal joint (elastic support) is located on load beam 66 and is movable at one end of flexible member 67. Magnetic head 14 is held in this universal joint. The other end of flexible member 67 is connected to FPC 18. Thus, FPC 18 is electrically connected to magnetic head 14 via wiring in flexible member 67.

[0078] As described above, one end of the FPC18 is connected to the flexible member 67. The other end of the FPC18 is electrically connected to the PCB19, for example, via a connector provided on the bottom wall 25.

[0079] Figure 2 The PCB 19 shown is located outside the housing 11 and mounted on the bottom wall 25. The PCB 19 houses, for example, a controller for controlling the HDD 10 and an interface connector for connecting to the host computer. The PCB 19 is electrically connected to the read / write head 14 via the FPC 18 and the flexible connector 67.

[0080] In this embodiment, the maximum thickness Db of the bottom wall 25 is set to be more than 1.5% and less than 8% of the maximum thickness Dh of the housing 11. The maximum thickness Db of the bottom wall 25 is the maximum distance between the inner surface 25a and the outer surface 25b of the bottom wall 25 in the Z direction. The maximum thickness Dh of the housing 11 is the maximum dimension of the housing 11 in the Z direction. In this embodiment, the maximum thickness Dh of the housing 11 is equal to the maximum dimension of the HDD 10 in the Z direction.

[0081] The maximum thickness Dh of the housing 11 is set to 26.2 mm or more. The Small Form Factor Committee (SFF-8300) sets several maximum dimensions (hereinafter referred to as specified dimensions) for the form factor of a 3.5-inch hard disk drive regarding the dimensions of the HDD in the Z direction. One specified dimension determined in SFF-8300 is 26.10 mm. That is, the maximum thickness Dh of the housing 11 in this embodiment is greater than this specified dimension.

[0082] More specifically, in this embodiment, the maximum thickness Dh of the housing 11 is set to be longer than 42 mm and less than 54 mm. Another specified dimension determined in SFF-8300 is 42.00 mm. That is, the maximum thickness Dh of the housing 11 in this embodiment is larger than this specified dimension.

[0083] For example, the maximum thickness Db of the bottom wall 25 is set to approximately 3.5 mm. On the other hand, the maximum thickness Dh of the housing 11 is set to approximately 54 mm. Thus, the thickness Db is approximately 6.5% of the thickness Dh. Furthermore, the thicknesses Db and Dh are not limited to this example.

[0084] In this embodiment, the dimension Dc of the coil 42 in the Z direction is set to be less than one-third of the maximum thickness Dh of the housing 11. For example, the dimension Dc of the coil 42 is set to approximately 14 mm. Thus, the dimension Dc is approximately 26% of the thickness Dh. In addition, the dimension Dc of the coil 42 is longer than the combined dimension (thickness) of the five disks 12 and the four spacers 34 in the Z direction.

[0085] The dimension Dc of the coil 42 in the Z direction is set as described in the example above, and the size of the coil 42 is compact relative to the housing 11. Furthermore, the distance between the two support members 48 of the bearing 33 located between the cover 22 and the coil 42 can be set to be relatively long, allowing the bearing 33 to stably support the rotor 32. Additionally, the thickness of the bottom wall 25 can also be set to be relatively long (thick), allowing the bottom wall 25 and the sleeve 41 to stably support the shaft 44. However, the dimension Dc is not limited to the example described above.

[0086] Figure 4 This is an illustrative cross-sectional view that schematically shows a portion of the HDD10 of the first embodiment. (See attached image.) Figure 4 As shown, the plurality of disks 12 in this embodiment include a plurality of first disks 71 and a plurality of second disks 72.

[0087] The plurality of first disks 71 are two or more disks 12 among the plurality of disks 12. The plurality of second disks 72 are the other two or more disks 12 among the plurality of disks 12. The first disks 71 and the second disks 72 are equal to each other except for their position and diameter.

[0088] The plurality of second disks 72 are further separated from the bottom wall 25 than the plurality of first disks 71. The diameter Dd1 of each of the plurality of first disks 71 is shorter than the diameter Dd2 of each of the plurality of second disks 72. For example, diameter Dd1 is 1 mm shorter than diameter Dd2.

[0089] Figure 5 This is an illustrative cross-sectional view that schematically shows another part of the HDD10 of the first embodiment. For example... Figure 5 As shown, the dimension (thickness) Td1 in the Z direction of each of the plurality of first disks 71 is longer (thicker) than the dimension (thickness) Td2 in the Z direction of each of the plurality of second disks 72. Furthermore, the diameter and thickness of the first disks 71 and the second disks 72 are not limited to this example.

[0090] like Figure 4 As shown, the sidewall 26 of the housing 11 also has an outer surface 26c and a parting line 26d. The parting line 26d is an example of a boundary line. The outer surface 26c is located on the opposite side of the shield 26b and is exposed on the outside of the housing 11. The parting line 26d is provided on the outer surface 26c. The parting line 26d is formed, for example, during the manufacture of the base 21 when the base 21 is removed from the mold. Furthermore, the boundary line is not limited to the parting line 26d formed in this way. The parting line 26d extends in a direction intersecting the Z direction.

[0091] The outer surface 26c has a first inclined surface 26e and a plane 26f. The first inclined surface 26e is an example of a first surface and a first inclined surface. The first inclined surface 26e and the plane 26f are arranged in the Z direction. The parting line 26d is the boundary line between the first inclined surface 26e and the plane 26f. In other words, the parting line 26d is the boundary line between two discontinuous surfaces.

[0092] The first inclined surface 26e is disposed between the end 11a of the housing 11 and the parting line 26d. The flat surface 26f is disposed between the end face 26a of the side wall 26 and the parting line 26d.

[0093] The first inclined plane 26e is inclined relative to the first rotation axis Ax1 in such a way that it separates from the first rotation axis Ax1 the closer it is to the parting line 26d. The plane 26f extends in the Z direction.

[0094] The protective cover 26b has a first protective cover 26g, a second protective cover 26h, and a step 26i. The first protective cover 26g is an example of a first inner surface. The second protective cover 26h is an example of a second inner surface. The step 26i is an example of a connecting surface.

[0095] The first shield 26g and the second shield 26h are each generally cylindrical curved surfaces extending about the first rotation axis Ax1. The first shield 26g faces the outer edge 12b of the first disk 71. The second shield 26h is separated from the bottom wall 25 than the first shield 26g. The second shield 26h faces the outer edge 12b of the second disk 72.

[0096] The diameter Di1 of the first shield 26g is shorter than the diameter Di2 of the second shield 26h. The distance between the first shield 26g and the outer edge 12b of the first disk 71 and the distance between the second shield 26h and the outer edge 12b of the second disk 72 are approximately equal.

[0097] Step 26i is disposed between the end of the first shield 26g in the +Z direction and the end of the second shield 26h in the -Z direction. Step 26i is generally oriented in the +Z direction. In other words, step 26i is oriented in a direction that intersects the direction in which the first shield 26g and the second shield 26h are oriented.

[0098] like Figure 5 As shown, the plurality of arms 62 includes a plurality of first arms 75 and a plurality of second arms 76. The plurality of first arms 75 are two or more of the plurality of arms 62. The plurality of second arms 76 are two or more other arms 62. The first arms 75 and the second arms 76 are equal to each other except for their position and thickness.

[0099] The plurality of second arms 76 are further separated from the bottom wall 25 than the plurality of first arms 75. The dimension (thickness) Ta1 in the Z direction of each of the plurality of first arms 75 is longer (thicker) than the dimension (thickness) Ta2 in the Z direction of each of the plurality of second arms 76. Furthermore, the thickness of the first arms 75 and the second arms 76 is not limited to this example.

[0100] The plurality of spacers 34 includes a plurality of first spacers 77 and a plurality of second spacers 78. The plurality of first spacers 77 are two or more of the plurality of spacers 34. The plurality of second spacers 78 are two or more of the other spacers 34. The first spacers 77 and the second spacers 78 are equal to each other except for their position and thickness.

[0101] The plurality of second spacers 78 are further separated from the bottom wall 25 than the plurality of first spacers 77. The dimension (thickness) Ts1 in the Z direction of each of the plurality of first spacers 77 is shorter (thicker) than the dimension (thickness) Ts2 in the Z direction of each of the plurality of second spacers 78. Furthermore, the thickness of the first spacers 77 and the second spacers 78 is not limited to this example.

[0102] In conventional HDDs, the maximum thickness in the Z-direction is set to 26.10 mm or less according to SFF-8300. For example, the thickness of conventional HDDs in the Z-direction is set to approximately 1 inch.

[0103] Sometimes, devices such as servers may house two conventional HDDs arranged in the Z-direction. In this case, each conventional HDD has a bottom wall and a cover. That is, there are two bottom walls and two covers. Furthermore, a gap exists between the two conventional HDDs.

[0104] On the other hand, the maximum thickness Dh in the Z direction of the housing 11 of the HDD10 in this embodiment is set to approximately 2 inches. That is, the thickness Dh in the Z direction of the HDD10 in this embodiment is set to approximately twice the thickness in the Z direction of a conventional HDD. Therefore, the HDD10 of this embodiment can be accommodated in a space (slot) in a server that can accommodate two conventional HDDs. In other words, a server can replace two conventional HDDs with one HDD10 of this embodiment.

[0105] The HDD 10 of this embodiment has a bottom wall 25 and a cover 22. Furthermore, there is no gap between two conventional HDDs in this HDD 10. Therefore, the size of the space (inner chamber S) in the Z direction that can accommodate the disk 12 in the HDD 10 of this embodiment is larger than the combined size of the space in the Z direction that can accommodate the disk in two conventional HDDs.

[0106] Based on the above, the HDD 10 of this embodiment can have more disks 12 than two conventional HDDs. For example, it is assumed that each of two conventional HDDs can hold nine disks. In the HDD 10 of this embodiment, as described above, the number of bottom walls 25 and covers 22 is small, and there are no gaps, so it can have more than 18 disks 12. Therefore, the storage capacity of the HDD 10 of this embodiment can be greater than the total storage capacity of two conventional HDDs.

[0107] HDD10 has one PCB19. On the other hand, two conventional HDDs together have two PCBs. Therefore, HDD10 of this embodiment can reduce the number of controllers mounted on PCB19 per unit of storage capacity, thereby reducing power consumption.

[0108] In the HDD 10 of the first embodiment described above, the housing 11 has a bottom wall 25, an inner surface 25a, an outer surface 25b, and a side wall 26. The bottom wall 25 is used to mount the spindle motor 13 and is separated from the plurality of disks 12 in the Z direction. The inner surface 25a is provided on the bottom wall 25 and faces the recording surface 12a of the disk 12. The outer surface 25b is provided on the bottom wall 25 and is located on the opposite side of the inner surface 25a. The side wall 26 protrudes from the bottom wall 25 and surrounds the plurality of disks 12 in a direction orthogonal to the Z direction. The maximum distance (thickness Db) between the inner surface 25a and the outer surface 25b in the Z direction is more than 1.5% and less than 8% of the maximum dimension (thickness Dh) of the housing 11 in the Z direction. As a result, the ratio of thickness Db to thickness Dh is small, and the housing 11 can accommodate a larger number of disks 12. Therefore, the HDD 10 of this embodiment can increase the storage capacity per unit volume of the HDD 10.

[0109] Each of the multiple disks 12 has a diameter Dd of 80 mm or more and 100 mm or less. That is, the diameter Dd of the multiple disks 12 is approximately 3.5 inches. The maximum thickness Dh of the housing 11 is 26.2 mm or more. That is, the maximum thickness Dh of the housing 11 is longer than one of the maximum dimensions in the Z direction of SFF-8300, which is 26.10 mm. Therefore, the HDD 10 of this embodiment is not limited by the maximum dimension in the Z direction of SFF-8300, and the number of disks 12 that can be accommodated in the housing 11 can be increased.

[0110] The maximum thickness Dh of the housing 11 is longer than 42 mm and less than 54 mm. That is, the maximum thickness Dh of the housing 11 is longer than another of the maximum dimensions in the Z direction of SFF-8300, which is 42.00 mm. In addition, the maximum thickness Dh of the housing 11 is approximately 2 inches. That is, the HDD 10 of this embodiment has approximately twice the size of a conventional HDD in the Z direction, corresponding to a form factor of 26.10 mm (approximately 1 inch) in the Z direction of SFF8300. Therefore, the HDD 10 of this embodiment can be accommodated in two slots that respectively accommodate conventional HDDs, and can be replaced by two conventional HDDs. When two conventional HDDs are accommodated in two slots, the thickness of the bottom wall and cover of the housing of each conventional HDD and the gap between the two conventional HDDs limit the storage capacity per unit space occupied by the HDD. However, the HDD 10 of this embodiment has only one bottom wall 25, and the aforementioned gap is not required. Therefore, the HDD 10 of this embodiment can increase the storage capacity per unit space occupied by the HDD 10.

[0111] The number of disks 12 is 20 or more. As a result, the HDD 10 can increase the storage capacity. In addition, since the size of the HDD 10 in the Z direction is about twice the size of two conventional HDDs, and the number of disks 12 in conventional HDDs is generally 9 or less, the HDD 10 of this embodiment can increase the storage capacity per unit volume of the HDD 10.

[0112] The diameter Ds of the shaft 44 is 5 mm or more and 10 mm or less. Generally, the diameter of the shaft in a conventional HDD spindle motor is 4 mm or less. Therefore, the HDD 10 of this embodiment can improve the rigidity of the shaft 44 and suppress the vibration of the rotor 32. On the other hand, if the diameter Ds of the shaft 44 is large, the distance between the shaft 44 and the coil 42 is reduced. However, in this embodiment, the bearing 33 and the coil 42 are arranged in the Z direction. Therefore, the HDD 10 can suppress interference between the bearing 33 and the coil 42.

[0113] The dimension Dc of the coil 42 in the Z direction is less than one-third of the maximum thickness Dh of the housing 11. In other words, the maximum thickness Dh of the housing 11 is more than three times the dimension Dc of the coil 42. Therefore, the maximum thickness Dh of the housing 11 increases, allowing for a larger number of disks 12 that can be accommodated. Thus, the HDD 10 of this embodiment can increase the storage capacity per unit volume. Furthermore, even when the bearing 33 and the coil 42 are arranged in the Z direction, the HDD 10 of this embodiment can achieve a relatively long rotor 32 supported by the bearing 33, thereby suppressing rotor 32 vibration.

[0114] The plurality of disks 12 include a first disk 71 and a second disk 72 that is further separated from the bottom wall 25 than the first disk 71. The diameter Dd1 of the first disk 71 is shorter than the diameter Dd2 of the second disk 72. The sidewall 26 has a first shield 26g extending about a first rotation axis Ax1 and facing the first disk 71, and a second shield 26h extending about a first rotation axis Ax1 and facing the second disk 72. The diameter Di1 of the first shield 26g is shorter than the diameter Di2 of the second shield 26h. Thus, even though the outer surface 25b of the sidewall 26 is provided with a first inclined surface 26e, the HDD 10 of this embodiment can suppress the thinning of the sidewall 26 near the bottom wall 25.

[0115] Each of the multiple carriages 55 has an arm 62, each capable of independently rotating about a second rotation axis Ax2 extending in the Z direction and separated from the first rotation axis Ax1 in a direction orthogonal to the first rotation axis Ax1. That is, the HDD 10 of this embodiment has so-called multiple actuators. Therefore, the HDD 10 can suppress the carriages 55 from becoming too heavy, thereby suppressing the decrease in angular acceleration of the carriages 55 relative to a predetermined drive current. Furthermore, when the HDD 10 includes multiple disks 12, including the first disk 71 and the second disk 72, it can suppress the complexity of rotational control of the carriages 55 (actuator assembly 15). In addition, the inspection time of the HDD 10 can be shortened.

[0116] Multiple arms 62 have a first arm 75 and a second arm 76 that is further separated from the bottom wall 25 than the first arm 75. The dimension Ta1 of the first arm 75 in the Z direction is longer than the dimension Ta2 of the second arm 76 in the Z direction. Multiple disks 12 have a first disk 71 and a second disk 72 that is further separated from the bottom wall 25 than the first disk 71. The dimension Td1 of the first disk 71 in the Z direction is longer than the dimension Td2 of the second disk 72 in the Z direction. Multiple spacers 34 have a first spacer 77 and a second spacer 78 that is further separated from the bottom wall 25 than the first spacer 77. The dimension Ts1 of the first spacer 77 in the Z direction is shorter than the dimension Ts2 of the second spacer 78 in the Z direction. Generally, the greater the separation of the disk 12 from the bottom wall 25 in the Z direction, the greater the error. By setting the above dimensions, the HDD 10 of this embodiment can set a large distance between the arm 62 and the disk 12 at the position separated from the bottom wall 25, thereby suppressing the arm 62 and the disk 12 from getting too close.

[0117] Multiple ramp loading mechanisms 17 are separated from the first rotation axis Ax1 and configured to hold multiple read / write heads 14 at a position separated from the disk 12. These multiple ramp loading mechanisms 17 are arranged in the Z direction. As a result, the HDD 10 of this embodiment can suppress the enlargement of each ramp loading mechanism 17, and thus can suppress the decrease in the dimensional accuracy of the ramp loading mechanisms 17.

[0118] (Second Implementation)

[0119] Hereinafter, regarding the second embodiment, refer to Figure 6 To illustrate. Furthermore, in the following descriptions of various embodiments, components having the same function as those already described are labeled with the same reference numerals, and sometimes the description is omitted. Additionally, the multiple components labeled with the same reference numerals are not limited to having all common functions and properties; they may also have different functions and properties corresponding to each embodiment.

[0120] Figure 6This is an illustrative cross-sectional view that schematically shows a portion of the HDD10 of the second embodiment. (See attached image.) Figure 6 As shown, in the second embodiment, the substrate 21 has a sidewall 126 instead of the sidewall 26. The sidewall 126 is an example of the second wall. The sidewall 126 is substantially the same as the sidewall 26 of the first embodiment, except for the points to be explained below.

[0121] The sidewall 126 replaces the plane 26f and has a second inclined surface 126f. The second inclined surface 126f is an example of the second surface and the second inclined surface. The first inclined surface 26e and the second inclined surface 126f are arranged in the Z direction. The parting line 26d is the boundary line between the first inclined surface 26e and the second inclined surface 126f.

[0122] The second inclined surface 126f is disposed between the end face 26a of the side wall 26 and the parting line 26d. The second inclined surface 126f is inclined relative to the first rotation axis Ax1 in such a way that the closer it is to the parting line 26d, the more it separates from the first rotation axis Ax1.

[0123] The absolute value of the angle θ1 between the first rotation axis Ax1 and the first inclined plane 26e is greater than the absolute value of the angle θ2 between the first rotation axis Ax1 and the second inclined plane 126f. Figure 6 For illustration, the angle between the Z-axis, which is parallel to the first rotation axis Ax1, and the first inclined plane 26e is denoted as angle θ1, and the angle between the Z-axis and the second inclined plane 126f is denoted as angle θ2.

[0124] In the second embodiment, the distance Dp in the Z direction between the parting line 26d and the end 11a of the housing 11 is set to be 27 mm or more and 40 mm or less. In other words, the parting line 26d is separated from the end face 26a of the sidewall 26 by 14 mm or more and 27 mm or less in the Z direction.

[0125] exist Figure 6 In the example, sidewall 126 does not have a second shield 26h and step 26i, and the plurality of disks 12 does not include the second disk 72. However, sidewall 126 may also have a second shield 26h, and the plurality of disks 12 may also include the second disk 72.

[0126] In the HDD10 of the second embodiment described above, the sidewall 126 has a first inclined surface 26e, a second inclined surface 126f, and a parting line 26d. The second inclined surface 126f and the first inclined surface 26e are arranged in the Z direction. The parting line 26d is the boundary line between the first inclined surface 26e and the second inclined surface 126f. The distance Dp in the Z direction between the parting line 26d and the end 11a of the housing 11 provided in the Z direction of the bottom wall 25 is 27 mm or more and 40 mm or less. Generally, the first inclined surface 26e is provided between the parting line 26d and the end 11a to facilitate disassembly from the mold. If the parting line 26d is far from the end 11a, the sidewall 126 becomes thinner near the bottom wall 25 due to the first inclined surface 26e. However, in the HDD10 of this embodiment, the parting line 26d is provided at the above position, which can suppress the thinning of the sidewall 126 near the bottom wall 25.

[0127] The sidewall 126 has an end face 26a. The end face 26a is located on the opposite side of the end 11a. A first inclined surface 26e is disposed between the end 11a and the parting line 26d, and is exposed on the outside of the housing 11. A second inclined surface 126f is disposed between the end face 26a and the parting line 26d, and is exposed on the outside of the housing 11. The first inclined surface 26e and the second inclined surface 126f are inclined relative to the first rotation axis Ax1 in such a way that the closer they are to the parting line 26d, the more they separate from the first rotation axis Ax1. Therefore, during the manufacture of the housing 11, the housing 11 can be easily removed from the mold.

[0128] The absolute value of the angle θ1 between the first rotation axis Ax1 and the first inclined plane 26e is greater than the absolute value of the angle θ2 between the first rotation axis Ax1 and the second inclined plane 126f. The housing 11 has a cover 22 fixed to the end face 26a. Because the angle θ2 between the first rotation axis Ax1 and the second inclined plane 126f is small, the end face 26a for fixing the cover 22 can maintain a size suitable for fixing the cover 22. Therefore, the HDD 10 of this embodiment can fix the cover 22 and the end face 26a to each other with sufficient strength.

[0129] (Third Implementation)

[0130] Hereinafter, regarding the third embodiment, refer to Figure 7 To illustrate. Figure 7 This is an illustrative cross-sectional view showing a portion of the HDD10 according to the third embodiment. (See attached image.) Figure 7 As shown, in the third embodiment, the HDD10 replaces the bearing 33, shaft 44, and hub 45 with bearing 233, shaft 244, and hub 245. The bearing 233, shaft 244, and hub 245 are substantially the same as the bearing 33, shaft 44, and hub 45, except for the points to be explained below.

[0131] The diameter Ds of shaft 244 is shorter than the diameter Ds of shaft 44 in the first embodiment. Therefore, shaft 244 is separated from coil 42. Shaft 244 has the rigidity to support rotor 32 via bearing 233.

[0132] The hub 245 replaces the second inner surface 45c and has a second inner surface 245c. The second inner surface 245c also faces the shaft 244 between the plurality of coils 42 and the shaft 244.

[0133] Bearing 233 is located radially between shaft 244 and coil 42. In other words, bearing 233 and coil 42 are arranged radially. One of the two support members 48 of bearing 233 is located between shaft 244 and coil 42.

[0134] In the HDD10 of the third embodiment described above, the bearing 233 is located radially between the shaft 244 and the coil 42. This allows for a relatively long rotor 32 supported by the bearing 233, thus suppressing rotor 32 vibration.

[0135] In the above description, suppression is defined, for example, as preventing the occurrence of an event, effect, or influence, or reducing the degree of an event, effect, or influence.

[0136] The foregoing has described some embodiments of the present invention, but these embodiments are provided by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a wide variety of other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and / or variations thereof are included in the scope and spirit of the invention, and are included in the scope of the invention as set forth in the claims and its equivalents.

Claims

1. A disk device comprising: Multiple disks, each having a recording surface, are arranged at intervals from each other along an axis intersecting the recording surfaces; A spindle motor configured to hold the plurality of disks and rotate the plurality of disks about a first rotation axis extending axially in the axial direction; and A housing having a first wall for mounting the spindle motor and separated from the plurality of disks in the axial direction, an inner surface disposed on the first wall and facing the recording surface, an outer surface disposed on the first wall and located on the opposite side of the inner surface, and a second wall protruding from the first wall and surrounding the plurality of disks in a direction orthogonal to the axial direction, for accommodating the plurality of disks. The maximum distance between the inner surface and the outer surface in the axial direction is more than 1.5% and less than 8% of the maximum thickness of the housing in the axial direction.

2. The disk device according to claim 1, The diameter of each of the plurality of disks is greater than 80mm and less than 100mm. The maximum thickness of the housing along the axial direction is 26.2 mm or more.

3. The disk device according to claim 2, The maximum thickness of the housing along the axial direction is longer than 42 mm and less than 54 mm.

4. The disc device according to any one of claims 1 to 3, The number of disks is 20 or more.

5. The disc device according to any one of claims 1 to 3, The spindle motor has a stator mounted on the first wall, a rotor configured to hold the plurality of disks and rotate relative to the stator about the first rotation axis, and bearings supporting the rotor in a manner that enables it to rotate about the first rotation axis. The stator has coils surrounding the first rotation axis. The stator or the rotor has a shaft extending along the first rotation axis. The diameter of the shaft is 5mm or more and 10mm or less. The bearing and the coil are arranged axially.

6. The disk device according to claim 5, The length of the coil along the axial direction is less than one-third of the maximum thickness of the housing along the axial direction.

7. The disc device according to any one of claims 1 to 3, The main spindle motor has coils surrounding the first rotating shaft. The length of the coil along the axial direction is less than one-third of the maximum thickness of the housing along the axial direction.

8. The disc device according to any one of claims 1 to 3, The second wall has a first surface, a second surface aligned with the first surface in the axial direction, and a boundary line between the first surface and the second surface. The axial distance between the boundary line and the first end of the housing located on the first wall is more than 27 mm and less than 40 mm.

9. The disk device according to claim 8, The second wall has a second end located on the opposite side of the first end. The first surface has a first inclined surface disposed between the first end and the boundary line and exposed on the outside of the housing. The second surface has a second inclined surface disposed between the second end and the boundary line and exposed on the outside of the housing. The first inclined plane and the second inclined plane are inclined relative to the first rotation axis in such a way that the closer they are to the boundary line, the more they separate from the first rotation axis.

10. The disk device according to claim 9, The absolute value of the angle between the first rotation axis and the first inclined plane is greater than the absolute value of the angle between the first rotation axis and the second inclined plane. The housing has a cover fixed to the second end.

11. The disc device according to any one of claims 1 to 3, The plurality of disks includes a first disk and a second disk that is separated from the first wall than the first disk. The diameter of the first disk is shorter than the diameter of the second disk. The second wall has a first inner surface extending about the first rotation axis and facing the first disk, and a second inner surface extending about the first rotation axis and facing the second disk. The diameter of the first inner surface is shorter than the diameter of the second inner surface.

12. The disk device according to claim 11, The second wall has a connecting surface disposed between the axial end of the first inner surface and the axial end of the second inner surface, facing a direction that intersects the direction of the first inner surface and the direction of the second inner surface.

13. The disc device according to any one of claims 1 to 3, further comprising: Multiple read / write heads are configured to read and write information on the disk. Multiple carriages, each having an arm, are each capable of independently rotating about a second rotation axis, the second rotation axis extending along the axial direction and separated from the first rotation axis in a direction orthogonal to the first rotation axis; and Multiple suspensions are respectively installed on a corresponding arm among the multiple carriages, and each holds a corresponding magnetic head among the multiple magnetic heads.

14. The disc device according to any one of claims 1 to 3, further comprising: Multiple read / write heads are configured to read and write information on the disk. The carriage has a plurality of arms arranged at intervals along the axial direction and is rotatable about a second rotation axis that extends along the axial direction and is separated from the first rotation axis in a direction orthogonal to the first rotation axis. Multiple suspensions are respectively installed on a corresponding arm of the multiple arms, and each arm holds a corresponding magnetic head of the multiple magnetic heads; and Multiple spacers are respectively disposed between two adjacent disks among the multiple disks. The plurality of arms has a first arm and a second arm, the second arm being separated from the first wall than the first arm. The thickness of the first arm in the axial direction is greater than the thickness of the second arm in the axial direction.

15. The disc device according to claim 14, The plurality of disks includes a first disk and a second disk that is separated from the first wall than the first disk. The thickness of the first disk along the axial direction is greater than the thickness of the second disk along the axial direction.

16. The disc device according to claim 14, The plurality of spacers includes a first spacer and a second spacer that is separated from the first wall than the first spacer. The thickness of the first spacer in the axial direction is smaller than the thickness of the second spacer in the axial direction.

17. The disc device according to any one of claims 1 to 3, further comprising: Multiple read / write heads are configured to read and write information on the disk. The carriage has a plurality of arms arranged at intervals along the axial direction and is rotatable about a second rotation axis that extends along the axial direction and is separated from the first rotation axis in a direction orthogonal to the first rotation axis. Multiple suspensions are respectively installed on a corresponding arm of the multiple arms, and each arm holds a corresponding magnetic head of the multiple magnetic heads; and Multiple spacers are respectively disposed between two adjacent disks among the multiple disks. The plurality of disks includes a first disk and a second disk that is separated from the first wall than the first disk. The thickness of the first disk along the axial direction is greater than the thickness of the second disk along the axial direction.

18. The disc device according to any one of claims 1 to 3, further comprising: Multiple read / write heads are configured to read and write information on the disk. The carriage has a plurality of arms arranged at intervals along the axial direction and is rotatable about a second rotation axis that extends along the axial direction and is separated from the first rotation axis in a direction orthogonal to the first rotation axis. Multiple suspensions are respectively installed on a corresponding arm of the multiple arms, and each arm holds a corresponding magnetic head of the multiple magnetic heads; and Multiple spacers are respectively disposed between two adjacent disks among the multiple disks. The plurality of spacers includes a first spacer and a second spacer that is separated from the first wall than the first spacer. The thickness of the first spacer in the axial direction is smaller than the thickness of the second spacer in the axial direction.

19. The disc device according to any one of claims 1 to 3, further comprising: Multiple read / write heads are configured to read and write information on the disk; and Multiple ramps are arranged along the axial direction to separate from the first rotation axis and to hold the multiple heads in a position separated from the disk.

Images