Disk device and method for manufacturing disk device

Abstract

Embodiments of the present invention provide a disk device and a manufacturing method thereof that can reduce height variations in stacked magnetic disks. According to the embodiment, the disk device includes: a housing having a base having a bottom wall and a cover fixed to the base; a drive motor having a pivot shaft erected from the bottom wall and a hub having an outer peripheral surface coaxial with the pivot shaft and an annular flange provided at an end of the outer peripheral surface on the bottom wall side, rotatably supported by the pivot shaft; ten or more magnetic disks mounted on the hub and stacked on the flange; and a plurality of spacer rings, one less than the number of magnetic disks, mounted on the hub and positioned between adjacent magnetic disks, stacked together with the magnetic disks on the flange. At least one of the spacer rings has a different thickness from the other spacer rings, and the difference between the maximum and minimum thicknesses of the spacer rings is 0.01 mm or more and 0.09 mm or less.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-098869 (filing date: June 14, 2021), and the entire contents of the basic application are incorporated herein by reference. Technical Field

[0002] Embodiments of the present invention relate to a disk device and a method for manufacturing the disk device. Background Art

[0003] A disk drive, such as a hard disk drive (HDD), includes a drive motor disposed in a housing and a plurality of rotatable magnetic disks stacked and arranged on a hub of the drive motor. Spacer rings are disposed between adjacent magnetic disks.

[0004] When multiple disks and spacers are stacked alternately, the stacking height may sometimes deviate due to manufacturing errors of the components. In particular, for the topmost disk, manufacturing errors of each part may accumulate, and therefore, the positional deviation relative to the set value may become larger. Summary of the Invention

[0005] An object of an embodiment of the present invention is to provide a disk device and a method for manufacturing the same that can reduce height variations among stacked magnetic disks.

[0006] According to an embodiment, a disk drive comprises: a housing having a base having a bottom wall and a cover fixed to the base; a drive motor having a pivot shaft erected from the bottom wall and a hub having an outer peripheral surface coaxial with the pivot shaft and an annular flange provided at an end of the outer peripheral surface on the bottom wall side, the hub being rotatably supported by the pivot shaft; ten or more magnetic disks mounted on the hub and stacked on the flange; and a plurality of spacer rings, one less than the number of magnetic disks, mounted on the hub and positioned between adjacent magnetic disks, stacked together with the magnetic disks on the flange. At least one of the spacer rings has a different thickness from the other spacer rings, and the difference between the maximum and minimum thicknesses of the spacer rings is 0.01 mm or more and 0.09 mm or less. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an exploded perspective view of the hard disk drive (HDD) according to the first embodiment, showing the top cover in an exploded manner.

[0008] Figure 2 is a top view of the HDD.

[0009] Figure 3 It is along Figure 2 A cross-sectional view of the HDD taken along line EE.

[0010] Figure 4 It is a perspective view showing the head actuator assembly and FPC unit of the HDD.

[0011] Figure 5 It is a side view showing the arrangement relationship between the head suspension assembly of the head actuator assembly and the magnetic disk.

[0012] Figure 6 It is a perspective view showing the slope of the HDD.

[0013] Figure 7 It is a side view showing the beak-shaped mouth portion of the slope in an enlarged manner.

[0014] Figure 8 1 is a flowchart showing the manufacturing process of the HDD.

[0015] Figure 9 It is a perspective view showing three types of spacer rings.

[0016] Figure 10 It is a top view of the HDD with the magnetic disk removed.

[0017] Figure 11 FIG. 1 is a top view of the base of the HDD.

[0018] Figure 12 This is a flowchart showing the manufacturing process of the HDD according to the sixth embodiment.

[0019] Figure 13A This is a diagram schematically showing the relationship between Z height deviation and height adjustment (no height adjustment) in the HDD manufacturing method according to the seventh embodiment.

[0020] Figure 13B This is a diagram schematically showing the relationship between Z height deviation and height adjustment (height adjustment at one location) in the HDD manufacturing method according to the seventh embodiment.

[0021] Figure 13C This is a diagram schematically showing the relationship between Z height deviation and height adjustment (height adjustment at three locations) in the HDD manufacturing method according to the seventh embodiment.

[0022] Description of labels

[0023] 10…housing, 12…base, 12a…bottom wall, 12b…side wall, 17…head, 18…disk, 19…spindle motor, 22…actuator assembly, 25…ramp loading mechanism, 30…suspension assembly, 32…arm, 64…hub, 65…flange, 66, 66(A), 66(B), 66(C)…spacer ring, 80…ramp DETAILED DESCRIPTION

[0024] Hereinafter, a disk device and a method for manufacturing the same according to an embodiment will be described with reference to the drawings.

[0025] Furthermore, the disclosure is merely an example, and appropriate modifications that can be readily conceived by those skilled in the art while maintaining the spirit of the invention are naturally within the scope of the present invention. Furthermore, in order to clarify the description, the drawings may schematically illustrate the sizes and shapes of various components compared to actual configurations. However, these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and the drawings, elements identical to those already described in the accompanying drawings may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0026] (First embodiment)

[0027] A hard disk drive (HDD) according to the first embodiment will be described in detail as the disk device.

[0028] Figure 1 This is an exploded perspective view of the HDD according to the first embodiment, showing the cover disassembled. Figure 2 This is a plan view of the HDD with its cover removed.

[0029] like Figure 1 As shown, the HDD has a roughly rectangular housing 10. The housing 10 has a rectangular box-shaped base 12 with an open upper surface, an inner cover 14 that is threadedly fastened to the base 12 by a plurality of screws 13 and closes the upper end opening of the base 12, and an outer cover (top cover) 16 that is overlapped with the inner cover 14 and welded to the base 12 at the periphery. The base 12 has a rectangular bottom wall 12a that is opposite to the inner cover 14 with a gap therebetween, and a side wall 12b that is erected along the periphery of the bottom wall 12a, and is integrally formed from, for example, an aluminum alloy. The side wall 12b includes a pair of long side walls that are opposite to each other and a pair of short side walls that are opposite to each other. A roughly rectangular frame-shaped fixing rib 12c is protruding from the upper end surface of the side wall 12b.

[0030] Positioning bosses B1 are protrudingly provided on the upper surfaces of the four corners of the side wall 12 b . The upper surfaces of the four positioning bosses B1 are planarized so as to be located at the same height and on the same plane, thereby constituting a height reference surface.

[0031] The inner cover 14 is formed into a rectangular plate shape from, for example, stainless steel. The inner cover 14 has its peripheral edge screwed to the upper surface of the side wall 12b by screws 13 and fixed to the inner side of the fixing rib 12c. The outer cover 16 is formed into a rectangular plate shape from, for example, aluminum. The outer cover 16 has a slightly larger planar dimension than the inner cover 14. The outer cover 16 has its peripheral edge welded to the fixing rib 12c of the base 12 over the entire circumference and is airtightly fixed to the base 12. A low-density gas, such as helium (He), having a density lower than that of air is enclosed in the airtightly sealed housing 10.

[0032] In addition, the height (thickness) H of the housing 10 (see Figure 3 ) According to the 3.5-inch HDD standard, it is formed to a maximum of 26.1mm or less.

[0033] Inside the housing 10, there are a plurality of, for example, ten, magnetic disks 18 serving as disc-shaped recording media, and a spindle motor 19 serving as a drive motor for supporting and rotating the magnetic disks 18. The spindle motor 19 is mounted on the bottom wall 12a. Each magnetic disk 18 is, for example, in the form of a disk having a diameter of 96 mm (3.5 inches) and a thickness of 0.5 to 0.635 mm. It has a substrate formed of a non-magnetic material such as glass or aluminum, and magnetic recording layers formed on the upper surface (first surface) and lower surface (second surface) of the substrate. In this embodiment, an aluminum substrate is used. The magnetic disks 18 are coaxially engaged with a hub (described later) of the spindle motor 19 and are clamped by a clamp spring 20. As a result, the magnetic disks 18 are supported parallel to the bottom wall 12a of the base 12. The multiple magnetic disks 18 are rotated at a predetermined rotational speed by the spindle motor 19. Furthermore, the number of magnetic disks 18 mounted is not limited to ten, but may be nine or fewer or eleven or more.

[0034] like Figure 1 and Figure 2 As shown, a plurality of magnetic heads 17 for recording and reproducing information on a magnetic disk 18 and an actuator assembly 22 for supporting these magnetic heads 17 so as to be movable relative to the magnetic disk 18 are provided within the housing 10. Furthermore, a voice coil motor (VCM) 24 for rotating and positioning the actuator assembly 22, a ramp loading mechanism 25 for holding the magnetic heads 17 in an unloaded position away from the magnetic disk 18 when the magnetic heads 17 move to the outermost periphery of the magnetic disk 18, a substrate unit (FPC unit) 21 on which electronic components such as a conversion connector are mounted, and a spoiler 70 are provided within the housing 10.

[0035] A printed circuit board 41 is screwed onto the outer surface of the bottom wall 12a of the base 12. The printed circuit board 41 constitutes a control unit that controls the operation of the spindle motor 19 and controls the operation of the VCM 24 and the magnetic head 17 via the board unit 21.

[0036] Figure 3 It is along Figure 2 A cross-sectional view of the HDD taken along line EE of FIG. In one example, the spindle motor 19 includes a pivot shaft 60 erected approximately vertically on the bottom wall 12a, a cylindrical rotating shaft 62 rotatably supported about the pivot shaft 60, a substantially cylindrical hub 64 coaxially fixed around the rotating shaft 62, a stator coil SC fixed to the bottom wall 12a and arranged around the rotating shaft 62, and a cylindrical magnet M mounted on the inner circumference of the hub 64 and facing the stator coil SC. The hub 64 has an outer circumferential surface coaxial with the pivot shaft 60 and an annular flange 65 integrally formed at the lower end (the end facing the bottom wall 12a) of the outer circumferential surface.

[0037] The disks 18 are engaged with the outer circumference of the hub 64, with the hub 64 inserted through its inner hole. An annular spacer ring 66 is attached to the outer circumference of the hub 64, sandwiching two adjacent disks 18. Multiple disks 18 and multiple spacer rings 66 are sequentially arranged on the flange 65 of the hub 64, attached to the hub 64 in an alternating, overlapping manner. A disc-shaped clamping spring 20 is attached to the upper end of the hub 64. The clamping spring 20 presses the inner circumferences of the multiple disks 18 and the spacer rings 66 toward the flange 65. This secures the multiple disks 18 in a stacked state, spaced apart at predetermined intervals. The ten disks 18 are supported so as to rotate integrally with the rotating shaft 62 and the hub 64. The ten disks 18 are supported parallel to each other and approximately parallel to the bottom wall 12a, spaced apart at predetermined intervals.

[0038] The height (thickness) H of the housing 10 is set to a maximum of 26.1 mm in accordance with HDD standards. The thickness TD of each magnetic disk 18 is set to be between 0.35 mm and 0.7 mm, and in this embodiment, is set to 0.635 mm. The thickness TS (axial thickness) of the spacer ring 66, which is the gap between two adjacent magnetic disks 18, is set to be between 1.2 mm and 1.5 mm. In this embodiment, a spacer ring 66 with a thickness TS of 1.462 mm is used as a reference. The spacer ring 66 is formed, for example, of aluminum.

[0039] As described above, according to this embodiment, ten magnetic disks 18 and nine spacer rings 66, one less than the number of magnetic disks, are stacked and arranged on the outer circumference of the hub 64 of the spindle motor 19. At least one of the nine spacer rings has a different thickness from the other spacer rings. The difference between the maximum and minimum thicknesses of the spacer rings 66 is set to be greater than 0.01 mm and less than 0.09 mm.

[0040] Figure 41 is a perspective view showing an actuator assembly. As shown in the figure, the actuator assembly 22 includes an actuator block 29 having a through hole 26, a bearing unit (unit bearing) 28 disposed in the through hole 26, a plurality of arms 32 extending from the actuator block 29, for example, 11 arms 32, a suspension assembly (head gimbal assembly: also referred to as HGA) 30 mounted on each arm 32, and the magnetic head 17 supported by the suspension assembly 30. A support shaft (pivot) 31 is provided upright on the bottom wall 12a of the base 12. The actuator block 29 is supported by the bearing unit 28 so as to be rotatable about the support shaft 31.

[0041] In this embodiment, the actuator block 29 and eleven arms 32 are integrally formed from aluminum or the like, forming a so-called E-block. The arms 32 are formed, for example, in the shape of elongated flat plates, extending from the actuator block 29 in a direction perpendicular to the support shaft 31. The eleven arms 32 are arranged parallel to each other with gaps therebetween.

[0042] The actuator assembly 22 includes a support frame 33 extending from the actuator block 29 in a direction opposite to the arm 32. The support frame 33 supports a voice coil 39 constituting a part of the VCM 24. Figure 1 As shown, the voice coil 39 is located between a pair of yokes 37 , one of which is fixed to the base 12 , and constitutes the VCM 24 together with these yokes 37 and a magnet fixed to one of the yokes.

[0043] like Figure 4 As shown, the actuator assembly 22 includes 20 suspension assemblies 30, each of which supports the magnetic head 17. The suspension assembly 30 is mounted on the extended end 32a of each arm 32. The plurality of suspension assemblies 30 include an upper suspension assembly that supports the magnetic head 17 upward and a lower suspension assembly that supports the magnetic head 17 downward. These upper suspension assemblies and lower suspension assemblies are formed by arranging the suspension assemblies 30 of the same structure in a manner that changes the vertical orientation.

[0044] In this embodiment, Figure 4 In the embodiment, the uppermost arm 32 is provided with a lower head suspension assembly 30, and the lowermost arm 32 is provided with an upper head suspension assembly 30. The nine arms 32 in the middle are each provided with an upper head suspension assembly 30 and a lower head suspension assembly 30.

[0045] The suspension assembly 30 includes a substantially rectangular base plate 38, a load beam 42 formed of an elongated leaf spring, and an elongated ribbon-shaped flexible member (wiring member) 40. The flexible member 40 has a freely displaceable universal joint portion, on which the magnetic head 17 is mounted. The base end portion of the base plate 38 is fixed to the installation surface (caulking surface) 32b of the extended end 32a of the arm 32 (see FIG. Figure 5), for example, by riveting. The base end of the load beam 42 is overlapped and fixed to the end of the substrate 38. The load beam 42 extends from the substrate 38 and tapers toward the extended end. The substrate 38 and the load beam 42 are formed, for example, from stainless steel.

[0046] The load beam 42 generates a spring force (reaction force) that urges the magnetic head 17 toward the surface of the magnetic disk 18. A protrusion 46 protrudes from the front end of the load beam 42. The protrusion 46 can engage with a ramp 80 described later and together with the ramp 80 constitutes the ramp loading mechanism 25.

[0047] like Figure 4 As shown, the substrate unit 21 integrally comprises a generally rectangular base portion 21a bent into an L-shape, a slender, strip-shaped intermediate portion 21b extending from one side edge of the base portion 21a, and a joint portion 21c continuously provided at the distal end of the intermediate portion 21b. The base portion 21a, intermediate portion 21b, and joint portion 21c are formed from a flexible printed circuit board (FPC). The FPC comprises an insulating layer, such as a polyimide layer, a conductive layer formed on the insulating layer and having a plurality of wiring lines, connection pads, and the like, formed thereon, and a protective layer covering the conductive layer.

[0048] Electronic components, such as a converter connector and multiple capacitors (not shown), are mounted on the base 21a and electrically connected to wiring (not shown). A metal plate serving as a reinforcing plate is attached to the base 21a. The base 21a is mounted on the bottom wall 12a of the base 12. The relay portion 21b extends from the side edge of the base 21a toward the actuator block 29 of the actuator assembly 22. The joint 21c, located at the extended end of the relay portion 21b, is formed into a rectangular shape with a height and width approximately equal to the side surface (mounting surface) of the actuator block 29. The joint 21c is attached to the mounting surface of the actuator block 29 via a backing plate formed from aluminum or the like and is threadedly secured to the mounting surface by fixing screws 72. Multiple connection pads are provided on the joint 21c. For example, a head IC (head amplifier) ​​67 is mounted on the joint 21c, which is connected to the connection pads and the base 21a via wiring. Furthermore, the joint portion 21 c is provided with a connection terminal 68 to which the voice coil 39 is connected.

[0049] The flexure 40 of each suspension assembly 30 has one end electrically connected to the magnetic head 17, another end extending to the actuator block 29 through a groove formed on the side edge of the arm 32, and a connection end (tail connection terminal portion) 48c provided at the other end. The connection end 48c is formed into an elongated rectangular shape. A plurality of, for example, 13 connection terminals (connection pads) 51 are provided at the connection end 48c. These connection terminals 51 are respectively connected to the wiring of the flexure 40. That is, the plurality of wirings of the flexure 40 extend over substantially the entire length of the flexure 40, one end being electrically connected to the magnetic head 17, and the other end being connected to the connection terminal (connection pad) 51.

[0050] The connection terminals 51 provided on the connection ends 48c of the twenty flexures 40 are bonded to the connection pads of the joint portion 21c and are electrically connected to the wiring of the joint portion 21c via the connection pads. Thus, the twenty magnetic heads 17 of the actuator assembly 22 are electrically connected to the base portion 21a via the wiring of the flexure 40, the connection ends 48c, the joint portion 21c of the substrate unit 21, and the relay portion 21b.

[0051] When the actuator assembly 22 constructed as described above is mounted on the base 12, the support shaft 31 is erected substantially parallel to the main shaft of the spindle motor 19. Each magnetic disk 18 is positioned between the two suspension assemblies 30. During operation of the HDD, the magnetic head 17 supported by the two suspension assemblies 30 faces the upper and lower surfaces of the magnetic disks 18, respectively.

[0052] Figure 5 1 is a side view showing the arrangement of the head suspension assembly 30 and the magnetic disk 18. As shown in the figure, when the HDD is in operation, each magnetic disk 18 is sandwiched between the lower head suspension assembly 30 and the upper head suspension assembly 30. The magnetic head 17 supported by the two suspension assemblies 30 is opposite to the upper and lower surfaces of the magnetic disk 18, respectively. In the figure, the distance between the mounting surface 32b of the front end 32a of the arm 32 and the surface of the magnetic disk 18 is referred to as the Z-height. According to this embodiment, the mounting height of the magnetic disk 18 is adjusted so that the Z-height is within an error range of ±0.06mm relative to a predetermined design value.

[0053] Next, the slope of the ramp loading mechanism 25 and the arrangement relationship between the slope and the magnetic disk 18 will be described in detail. Figure 6 is a perspective view showing the ramp of the ramp loading mechanism, Figure 7 It is a side view schematically showing the entrance and exit (beak) portion of the slope.

[0054] The ramp loading mechanism 25 has a ramp 80. Figure 1 As shown, the ramp 80 is fixed to the bottom wall 12a of the base 12 and is located near the periphery of the magnetic disk 18. When the HDD is not in operation, if the magnetic head 17 is separated from the outer periphery of the magnetic disk 18 and moves to a predetermined stop position, the protrusion 46 of the suspension assembly 30 jumps onto the ramp 80. As a result, the magnetic head 17 is held at a position away from the magnetic disk 18.

[0055] like Figure 6As shown, the ramp 80 comprises a rectangular plate-shaped ramp body 82, ten guide blocks 84 projecting from one side of the ramp body, and a support bracket 85 projecting from the other side of the ramp body 82. The ramp body 80 is integrally formed from, for example, synthetic resin or metal. By securing the support bracket 85 to the base 12, the ramp body 82 is positioned so as to stand substantially perpendicular to the base's bottom wall 12a.

[0056] The guide block 84 has an elongated rectangular parallelepiped shape and extends substantially parallel to the bottom wall 12a. Ten guide blocks 84 are arranged at predetermined intervals in the axial direction of the magnetic disk 18. A rectangular recess (notch) 86 is formed at one end of each guide block 84 on the magnetic disk 18 side. Figure 3 and Figure 7 As shown, in a state where the slope 80 is provided on the base 12 , the outer peripheral edge portions of the ten magnetic disks 18 are positioned in the recesses 86 of the corresponding guide blocks with gaps (intervals) therebetween.

[0057] like Figure 6 and Figure 7 As shown, each guide block 84 has an upper guide surface (first guide surface) Ga for guiding and supporting the tab 46 of the lower head suspension assembly 30, and a lower guide surface (second guide surface) Gb for guiding and supporting the tab 46 of the upper head suspension assembly 30. The upper guide surface Ga and the lower guide surface Gb are located opposite each other and are provided substantially perpendicularly to one surface of the ramp body 82.

[0058] The upper guide surfaces Ga and lower guide surfaces Gb of the ten guide blocks 84 are arranged at predetermined intervals along the axial direction of the magnetic disk 18 and are positioned to match the height of the corresponding suspension assembly 30. Each guide surface Ga and Gb extends substantially along the radius of the magnetic disk 18 to near the outer periphery of the magnetic disk 18 and is positioned in the movement path of the tab 54.

[0059] The upper guide surface Ga has a first inclined surface 87a that extends obliquely from near the surface of the magnetic disk 18 (near the recess 86) in a direction away from the magnetic disk 18, here upward, and is used to load and unload the magnetic head 17 onto the magnetic disk, a supporting surface 87b that extends following the first inclined surface 87a and is approximately parallel to the magnetic disk surface, and a second inclined surface 87c that extends obliquely from the other end of the supporting surface 87b to the end of the guide surface.

[0060] Similarly, the lower guide surface Gb has a first inclined surface 88a that extends obliquely from near the surface of the magnetic disk 18 (near the recess 86) in a direction away from the magnetic disk 18, here downward, and is used to load and unload the magnetic head 17 onto the magnetic disk, a supporting surface 88b that extends following the first inclined surface 88a and is approximately parallel to the magnetic disk surface, and a second inclined surface 88c that extends obliquely from the other end of the supporting surface 88b to the end of the guide surface.

[0061] like Figure 7 As shown, the gap B between the slope 80 and the surface of the magnetic disk 18, which is one of the parameters that determine the resistance of the disk drive to shock during operation, is preferably set to a predetermined value, for example, approximately 0.275 mm. Therefore, the installation height of the magnetic disk 18 is adjusted so that the center axis CD of the magnetic disk 18 in the thickness direction and the center axis CR of the recess 86 of the slope 80 in the height direction coincide with each other or are within a deviation range of ±0.06 mm.

[0062] In the HDD, the actuator assembly 22 is rotated about the support shaft 31 using the VCM 24, causing the multiple magnetic heads 17 to move to desired seek positions relative to the surfaces of the respective magnetic disks 18. When the HDD is not in operation, if the magnetic heads 17 are separated from the outer periphery of the magnetic disks 18 and move to a predetermined stop position, the tabs 46 of the multiple suspension assemblies 30 each jump onto the upper guide surface Ga and lower guide surface Gb of the corresponding ramps 80. As a result, the ramps 80 hold the magnetic heads 17 in an unloaded position away from the magnetic disks 18.

[0063] Next, a method for manufacturing the HDD having the above-described structure will be described.

[0064] In the aforementioned HDD, the thickness of the disks 18 and the thickness of the spacer rings 66 preferably have a deviation of zero from the design values. However, due to manufacturing variations, larger disks must tolerate a deviation of approximately ±0.01 mm, while smaller spacer rings must tolerate a deviation of approximately ±0.005 mm. However, as the number of disks mounted increases, the cumulative thickness variations of the stacked disks and spacer rings increase, and the impact of these variations increases with the uppermost disks. For example, if ten disks 18 are mounted, and a stack of disks 0.01 mm thick and spacer rings 0.005 mm thick relative to the design values ​​is stacked, the height of the topmost disk surface will deviate from the design value by 0.01 × 10 + 0.005 × 9 = 0.145 mm.

[0065] Therefore, in the HDD and the manufacturing method thereof according to the present embodiment, the height variation of the magnetic disk is reduced by adjusting the thickness of the spacer ring.

[0066] Figure 8 is a flowchart showing the manufacturing process of an HDD. Figure 9 is a perspective view showing three types of spacer rings with different thicknesses, Figure 10 is a top view of the HDD with the disk removed. Figure 11 FIG. 1 is a top view of the base of the HDD.

[0067] like Figure 8As shown, in the manufacturing method, first, assume that the number of stacked spacer rings n = 1 (the first sheet) and the deviation ΔS0 of the thickness of the disk 18 from the design center value is 0 (ST1). Measure the height of the upper surface of the flange 65 of the hub 64 of the spindle motor 19 (ST2). In one example, as Figure 10 shown, taking the height of the upper surfaces of the four positioning bosses B1 provided on the base 12 as a reference, measure the height of the upper surface of the flange 65 using a measuring instrument such as a laser displacement meter or a capacitance displacement meter. Set the difference (height deviation) between the measured height and the design center value as t0 (a positive value indicates the case where the hub 64 is closer to the top cover side), and manage it in association with the spindle motor 19.

[0068] In the case of this embodiment, manage it so that t0 is, for example, -0.05 mm or more and +0.05 mm or less, and do not use a spindle motor that exceeds this range.

[0069] Next, as Figure 8 shown, measure the thickness of the inner peripheral portion of the first stacked disk 18, and set the difference (thickness deviation) between the measured thickness and the design center value as Δm1 (ST3). After measuring the thickness, stack the disk 18 on the flange 65 of the hub 64 (ST4).

[0070] Regarding the spacer ring 66, prepare two or more types with different design center values, for example, three spacer rings. In this embodiment, as Figure 9 shown, use the A-grade spacer ring (A) 66: thickness TS1: 1.452 mm ± 0.005 mm, the B-grade spacer ring (B) 66: thickness TS2: 1.462 mm ± 0.005 mm, and the C-grade spacer ring (C) 66: thickness TS3: 1.472 mm ± 0.005 mm, these three spacer rings with different thicknesses (TS1 < TS2 < TS3). Since the thickness tolerance is ±0.005 mm, there is no overlap in the thickness of the spacer rings belonging to grades A, B, and C.

[0071] In addition, in order to easily distinguish the types, marks M, such as dots, can also be marked on the spacer ring 66. The A-grade spacer ring (A) 66 is marked with 1 dot, the B-grade spacer ring (B) 66 is marked with 2 dots, and the C-grade spacer ring (C) 66 is marked with 3 dots. The mark M is not limited to dots, and various options such as barcodes are available.

[0072] Next, as Figure 8 shown, calculate the value obtained by adding the difference Δm1 of the stacked disk 18 to the difference t0 associated with the spindle motor 19 as the height t1 of the surface of the first disk 18 (ST5). Determine the grade of the first stacked spacer ring 66 according to the magnitude of t1 (ST6 to ST10).

[0073] When t1 < -0.01 (ST6), select the spacer ring 66(C) of grade C (ST8).

[0074] When -0.01 ≤ t1 ≤ 0.01 (ST7), select the spacer ring 66(B) of grade B.

[0075] When 0.01 < t1 (ST7), select the spacer ring 66(A) of grade A (ST10).

[0076] Measure the thickness of the selected first spacer ring 66, and set the deviation of the measured value from the design center value as ΔS1 (ST11). After the measurement, stack the spacer ring 66 on the first disk 18 (ST12).

[0077] When the number of stacked spacer rings n is less than 9 (ST13), set n = n + 1 (ST14), and repeatedly execute the processes (ST3) to (ST13). That is, continue to stack the second disk 18 on the spacer ring 66. Measure the thickness of the inner peripheral part of the disk 18 before stacking, and set the deviation of the measured value from the design center value as Δm2 (ST3). Stack the measured second disk 18 on the spacer ring 66 (ST4).

[0078] Before stacking the second spacer ring, calculate the height t2 of the upper surface of the second disk 18 = t1 + ΔS1 + Δm2 (ST5). Determine the grade of the second stacked spacer ring according to the magnitude of the height t2 (ST6 - ST10).

[0079] When t2 < -0.01 (ST6), select the spacer ring 6( C) of grade C (ST8).

[0080] When -0.01 ≤ t2 ≤ 0.01 (ST7), select the spacer ring 66(B) of grade B.

[0081] When 0.01 < t2 (ST7), select the spacer ring 66(A) of grade A (ST10).

[0082] Measure the thickness of the selected second spacer ring 66, and set the deviation of the measured value from the design center value as ΔS2 (ST11). After the measurement, stack the spacer ring 66 on the second disk 18 (ST12).

[0083] The above steps ST3 to ST12 are repeated until nine disks 18 and nine spacer rings 66 are stacked. After the ninth spacer ring 66 is stacked (ST13), the tenth disk 18 is stacked on the spacer ring 66 (ST15). Then, the clamp spring 20 is attached to the hub 64, and the clamp spring 20 holds the ten disks 18 and nine spacer rings 66 in the stacked state (ST16).

[0084] As described above, according to this embodiment, ten magnetic disks 18 and nine spacer rings 66, one less than the number of magnetic disks, are stacked and arranged on the outer circumference of the hub 64 of the spindle motor 19. At least one of the nine spacer rings has a different thickness from the other spacer rings. The difference between the maximum and minimum thicknesses of the spacer rings 66 is set to be greater than 0.01 mm and less than 0.09 mm.

[0085] According to this embodiment, the optimal thickness of the spacer ring is selected based on the height deviation of the flange 65 and the thickness deviation of the magnetic disk 18, and the spacer ring is stacked. As a result, no magnetic disk will be generated that causes a height deviation exceeding the height deviation of the first stacked magnetic disk 18 (maximum 0.06mm), and 10 magnetic disks 18 can be stacked and arranged at a desired height position. The Z height of each suspension assembly 30 and the height position of the center axis CD of each magnetic disk 18 relative to the slope 80 can be within the range of the desired design value. Even when many, for example, 10 magnetic disks 18 are mounted, there will be no adverse conditions such as the floating change of the magnetic head and the inability of the head actuator to perform normal loading / unloading operations, and the disk device can be increased in capacity.

[0086] Next, HDDs and methods of manufacturing the same according to other embodiments of the present invention are described. In the other embodiments described below, the same reference numerals are used for the same parts as those in the first embodiment, and their detailed descriptions are omitted or simplified. The description will focus on the parts that differ from the first embodiment.

[0087] (Second embodiment)

[0088] Reference Figure 7 、 Figure 8 、 Figure 10 A method for manufacturing an HDD according to the second embodiment will be described.

[0089] like Figure 7 As shown, in order for the magnetic head to reliably perform loading / unloading operations between the ramp 80 and the magnetic disk 18 , it is preferable that the relative height B between the magnetic disk 18 and the ramp 80 has a small deviation from the designed center value.

[0090] In the first embodiment described above, as Figure 8In the example t0, the deviation of the height of the flange 65 of the motor hub 64 from the design value is used. However, in the second embodiment, the deviation of the height of the flange 65 relative to the height of the slope 80 is used as t0.

[0091] In detail, Figure 10 As shown, the height of the top surface of flange 65 is measured at three points, Z1, Z2, and Z3, on the top surface of flange 65, with the top surface of boss B1 as a reference. The height deviation of an imaginary point Zr from the design value, obtained by extending the plane formed by the heights of the three points to a position near slope 80 (radius R2), is used as t0. In this embodiment, Z1, Z2, and Z3 are arranged at equal intervals of an angle θ1 = 120° in the circumferential direction around the center axis of spindle motor 19. Z1, Z2, and Z3 are each arranged at a radius R1 = 14.5 mm, and Zr is set at a radius R2 = 46.6 mm.

[0092] By using the deviation t0 Figure 8 In the steps ST1 to ST16 shown, ten magnetic disks 18 and nine spacer rings are stacked on the flange 65 of the hub 64 .

[0093] According to the second embodiment described above, as in the first embodiment, by selecting and stacking spacer rings of optimal thickness based on the height variations of the flange 65 and the thickness variations of the magnetic disks 18, ten magnetic disks 18 can be stacked and arranged at a desired height relative to the slope 80. Furthermore, in the second embodiment, the height variations of the magnetic disks 18 near the slope 80 caused by the inclination of the hub 64 can also be taken into account, thereby enabling more effective height adjustment.

[0094] (Third embodiment)

[0095] Reference Figure 3 、 Figure 8 , a method for manufacturing an HDD according to the third embodiment will be described.

[0096] like Figure 3 As shown, the magnetic disks 18 and spacer rings 66 stacked on the hub 64 of the spindle motor 19 are fixed to the hub 64 while being pressed axially by the clamp spring 20. For example, when stacking ten magnetic disks 18 each 0.635 mm thick, an axial force of approximately 1200 N must be applied to the disks 18 to prevent them from shifting even after an impact of approximately 200 G. This axial force slightly deforms the flange 65 of the hub 64, sometimes causing the height of the mounted magnetic disks 18 to vary by approximately 0.01 mm. This variation contributes to the height deviation of the magnetic disks.

[0097] Therefore, in the third embodiment, the deflection amount Δh of the flange 65 due to the load of the clamp spring 20 is obtained in advance using another sample, and Figure 8 In step ST2, Δh is subtracted from the measured t0. Figure 8 In the steps ST3 to ST16 shown, ten magnetic disks 18 and nine spacer rings are stacked on the flange 65 of the hub 64 .

[0098] According to the third embodiment, the level of the spacer ring 66 can be appropriately selected by taking into account the height deviation Δh of the flange 65 caused by deformation during installation of the clamping spring, thereby enabling more effective adjustment of the height of the clamped magnetic disk. Specifically, the height adjustment can be performed so that the height deviation of the flange caused by the clamping spring is not propagated as a height deviation of the magnetic disk that is not directly in contact with the flange, or so that the height deviation of the magnetic disk is reduced.

[0099] (Fourth embodiment)

[0100] Reference Figure 7 、 Figure 8 、 Figure 11 , a method for manufacturing an HDD according to a fourth embodiment will be described.

[0101] like Figure 7 As shown, in order for the magnetic head to reliably perform loading / unloading operations between the ramp 80 and the magnetic disk 18 , it is preferable that the relative height B between the magnetic disk 18 and the ramp 80 has a small deviation from the designed center value.

[0102] like Figure 11 As shown, a slope 80 installation surface Zb is formed on the inner surface of the bottom wall 12a of the base 12. The installation surface Zb is formed with high precision by machining, but even in this case, a machining deviation of about ±0.03mm in the height direction cannot be avoided. Therefore, in the fourth embodiment, the height of the slope installation surface Zb is measured with the upper surface of the boss B1 as a reference, and the deviation ΔZb of the measured value from the design center value is calculated. Figure 8 In step ST2, ΔZb is subtracted from the measured t0. Figure 8 In the steps ST3 to ST16 shown, ten magnetic disks 18 and nine spacer rings are stacked on the flange 65 of the hub 64 .

[0103] According to the fourth embodiment, by subtracting the height deviation ΔZb of the sloped surface, the thickness of the spacer ring 66 can be selected to reduce the influence of the height deviation of the sloped surface, thereby optimizing the magnetic disk height position.

[0104] (Fifth embodiment)

[0105] Reference Figure 8 、 Figure 11 , a method for manufacturing an HDD according to the fifth embodiment is described.

[0106] like Figure 11 As shown, a mounting surface Zp for the actuator assembly 22 is formed on the inner surface of the bottom wall 12a of the base 12. A support shaft 31 is provided on this mounting surface Zp for rotatably supporting the actuator block. While the mounting surface Zp is formed with high precision through machining, even this method inevitably results in machining variations of approximately ±0.03 mm in height.

[0107] If the height of the installation surface Zp deviates from the design value, the height positions of the actuator assembly 22 and the suspension assembly 30 will deviate. The deviation in the height position of the suspension assembly 30 becomes a deviation in the Z height, which is a factor in the floating fluctuation of the magnetic head. Therefore, it is preferable that the deviation of the Z height from the design center value is small.

[0108] Therefore, according to the fifth embodiment, the height of the installation surface Zp of the head actuator is measured with the upper surface of the boss B1 as a reference, and the deviation ΔZp of the measured value from the design center value is calculated. Figure 8 In step ST2, ΔZp is subtracted from the measured t0. Figure 8 In the steps ST3 to ST16 shown, ten magnetic disks 18 and nine spacer rings are stacked on the flange 65 of the hub 64 .

[0109] According to the fifth embodiment, the level of the spacer ring 66 can be appropriately selected by taking into account the height deviation of the actuator installation surface Zp, that is, the height deviation (ΔZp) of the suspension assembly 30, thereby more effectively adjusting the height position and Z height of the magnetic disk. In other words, the height adjustment can be performed so that the height deviation of the installation surface Zp is not propagated as a height deviation of the magnetic disk that is not directly in contact with the flange, or so that the height deviation of the magnetic disk is reduced.

[0110] (Sixth embodiment)

[0111] Figure 12 This is a flowchart showing a method for manufacturing an HDD according to the sixth embodiment.

[0112] In the first to fifth embodiments described above, the disks and spacer rings are stacked while sequentially measuring the height deviation t0 of the spindle motor flange, the thickness deviation Δm of the disk 18, and the thickness deviation Δs of the spacer ring 66 during the HDD manufacturing process.

[0113] In contrast, according to the sixth embodiment, the height deviation t0 of the flange 65 of the spindle motor, the thickness deviation Δm of each magnetic disk 18, and the thickness Δs of each spacer ring 66 are measured in advance in units of components, and the measured values ​​are stored in association with each individual or as a batch (lot) average value, and each measured value is used as data during manufacturing.

[0114] like Figure 12 As shown, first, the flange height deviation t0 is read (ST1), and then the thickness deviation Δm1 of the first magnetic disk is read (ST2). Next, the first magnetic disk is stacked on the flange 65 (ST4), and the height deviation of the top surface of the first magnetic disk is calculated (t1 = t0 + Δm1) (ST5).

[0115] Based on the calculated size of the deviation t1, the optimum spacer ring 66 is selected, and data of the thickness deviation Δs1 of the selected spacer ring is read (ST to ST11).

[0116] If the number n of stacked spacer rings 66 is less than 9 (ST13), n is set to n+1 (ST14), and steps (ST3) to (ST13) are repeated. Specifically, the second disk 18 is stacked onto the spacer ring 66. After stacking, the thickness deviation Δm2 of the second disk 18 is read, and the height of the top surface of the second disk 18 is calculated (t2 = t1 + ΔS1 + Δm2) (ST5). The level of the second stacked spacer ring is determined based on the height t2 (ST6 to ST10).

[0117] After the thickness deviation ΔS2 of the selected second spacer ring 66 is read ( ST11 ), the spacer ring 66 is stacked on the second magnetic disk 18 ( ST12 ).

[0118] The above steps ST3 to ST12 are repeated until nine disks 18 and nine spacer rings 66 are stacked. After the ninth spacer ring 66 is stacked (ST13), the tenth disk 18 is stacked on the spacer ring 66 (ST15). Then, the clamp spring 20 is attached to the hub 64, and the clamp spring 20 holds the ten disks 18 and nine spacer rings 66 in the stacked state (ST16).

[0119] According to the manufacturing method of the sixth embodiment, it is possible to improve manufacturing efficiency compared to a method of measuring the amount of variation in each process.

[0120] (Seventh embodiment)

[0121] Figure 13A 、 Figure 13B 、 Figure 13CEach of them is a diagram schematically showing the relationship between Z-height deviation and height adjustment in the HDD manufacturing method according to the seventh embodiment.

[0122] According to the seventh embodiment, the thickness grade is not selected for all the stacked spacer rings 66, but is selected for only a few of the spacer rings, and the other spacer rings use the thickness center grade, for example, the B grade spacer ring.

[0123] For example, if there are 10 disks to be stacked, the average disk thickness is the design center value + 0.005 mm (5 μm), and the height deviation of the flange 65 is + 0.04 mm (40 μm), and the disks and the spacer rings are stacked without selecting the level of the spacer ring 66 (A. No height adjustment), then Figure 13A As shown in FIG. 1 , the height deviation generated when the tenth magnetic disk was stacked was +0.09 mm.

[0124] In contrast, according to this embodiment, Figure 13B As shown in the figure, for example, a spacer ring 66 stacked between the first and second disks is selected with a thickness of -0.05 mm relative to the design center value. In this case, even if the spacer ring 66 is selected only once, the stacking height deviation of the top surface of the tenth disk can be suppressed to +0.05 mm.

[0125] Furthermore, when the level selection of the spacer ring 66 is increased to 3 times, as shown in FIG. Figure 13C As shown, by, for example, selecting a spacer ring 66 with a grade of -0.02 mm relative to the thickness design center value for the spacer ring 66 inserted between the 1st and 2nd disks, between the 4th and 5th disks, and between the 7th and 8th disks, the stacking height deviation of the upper surface of the 10th disk can be suppressed to +0.04 mm.

[0126] As described above, according to the seventh embodiment, by selecting the thickness grade of the spacer ring only a few times and using the thickness center grade, such as grade B, for other spacer rings, the height deviation of the disk can be reduced, and the disk stacking equipment can be simplified to improve manufacturing efficiency.

[0127] As described above, according to the HDD of the aforementioned embodiment, spacer rings of optimal thickness are selected based on the height variations of the flange 65 and the thickness variations of the magnetic disks 18, and are then stacked. Multiple magnetic disks 18 and one fewer spacer ring 66 than the number of magnetic disks are stacked on the outer circumference of the hub 64 of the spindle motor 19. At least one of the multiple spacer rings has a different thickness from the other spacer rings. The difference between the maximum and minimum thicknesses of the spacer rings 66 is set to be between 0.01 mm and 0.09 mm.

[0128] Thus, according to the aforementioned embodiment, it is possible to provide a disk device and a method for manufacturing the same that can reduce height variations of stacked magnetic disks.

[0129] The present invention is not limited to the above-described embodiments as such. During implementation, the constituent elements may be modified and concretized within the scope of the present invention. In addition, various inventions may be formed by appropriately combining the multiple constituent elements disclosed in the above-described embodiments. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiments. Furthermore, constituent elements across different embodiments may be appropriately combined.

[0130] In the above embodiment, the number of magnetic disks is not limited to 10 and can be set to 11 or more. The thickness of the magnetic disks is not limited to 0.635 mm or 0.5 mm and can be varied as needed. Similarly, the diameter of the magnetic disks is not limited to 96 mm and can be set to 95 mm or 97 mm, for example. The material of the magnetic disks is not limited to aluminum and can also be glass. The material of the spacer rings is also not limited to aluminum and can also be titanium, stainless steel, glass, etc.

[0131] The heights of the housing base's sloped mounting surface, the actuator mounting surface, and the flange, as well as the disk thickness and the spacer ring thickness, can be measured in advance for each component and the measured values ​​used. The disk thickness can also be measured using a batch average or a cassette average rather than individual thicknesses. Furthermore, depending on the stacking height variations of the disks, the height variations of the sloped mounting surface, and the actuator mounting surface, different slope and / or actuator heights can be used, or the heights of the slope and / or actuator can be adjusted.

Claims

1. A disk device comprising: a housing having a base having a bottom wall and a cover fixed to the base; a drive motor comprising a pivot shaft erected on the bottom wall and a hub having an outer peripheral surface coaxial with the pivot shaft and an annular flange provided at an end portion of the outer peripheral surface on the bottom wall side, the hub being rotatably supported on the pivot shaft; Ten or more magnetic disks are mounted on the hub and stacked on the flange; and A plurality of spacer rings, one less than the number of the disks, are respectively mounted on the hub and located between adjacent disks, and are stacked together with the disks on the flange. At least one spacer ring has a thickness different from that of the other spacer rings, and a difference between a maximum thickness and a minimum thickness of the spacer ring is 0.01 mm or more and 0.09 mm or less.

2. The disk device according to claim 1, The at least one spacer ring is a spacer ring stacked on the magnetic disk closest to the flange.

3. The disk device according to claim 1, Some of the spacer rings among the plurality of spacer rings have different thicknesses from the other spacer rings, and a difference between a maximum thickness and a minimum thickness of the spacer rings is 0.01 mm or more and 0.09 mm or less.

4. The disk device according to claim 1, The invention also includes a head actuator, which includes: an actuator block rotatably supported on the bottom wall; a plurality of arms respectively extending from the actuator block and having a setting surface at the extension end; and a plurality of suspension assemblies, each including a support plate extending from the arm and fixed to the setting surface and a magnetic head supported on the extension end of the support plate. The distance between the installation surface of the arm and the opposing surface of the magnetic disk is set within an error range of ±0.06 mm relative to a predetermined design value.

5. The disk device according to claim 1, The device further comprises a slope provided on the bottom wall and arranged adjacent to the outer peripheries of the plurality of magnetic disks. The slope includes a plurality of recesses for arranging the outer periphery of the magnetic disk and a pair of guide surfaces extending from the vicinity of each recess and facing each other. The central axis of the magnetic disk in the thickness direction and the central axis of the concave portion of the slope in the height direction are consistent with each other or are within a deviation range of ±0.06 mm.

6. The disk device according to claim 1, The housing is filled with a low-density gas having a density lower than that of air.

7. The disk device according to claim 1, The housing has a height that is not more than the maximum height of 26.1 mm specified in the standard for 3.5-inch disk devices.

8. A method for manufacturing a disk device, wherein the disk device comprises: a housing having a base having a bottom wall and a cover fixed to the base; a drive motor having a pivot shaft and a hub erected on the bottom wall, the hub having an outer peripheral surface coaxial with the pivot shaft and an annular flange provided at an end portion of the outer peripheral surface on the bottom wall side, and being rotatably supported on the pivot shaft; at least ten magnetic disks mounted on the hub shaft and stacked on the flange; and a plurality of spacer rings, one less than the number of magnetic disks, mounted on the hub shaft and located between adjacent magnetic disks, and stacked together with the magnetic disks on the flange. The method for manufacturing the disk device includes: Two or more spacer rings having different thicknesses are prepared, wherein at least one spacer ring has a different thickness from the other spacer rings, and the difference between the maximum thickness and the minimum thickness of the spacer rings is 0.01 mm or more and 0.09 mm or less; measuring the height of the flange and calculating the height deviation from a predetermined design center value; Measure the thickness of the first disk and calculate the thickness deviation from the predetermined design center value; Laminating the first magnetic disk on the flange; Calculating a height deviation of the upper surface of the first stacked magnetic disk based on a height deviation of the flange and a thickness deviation of the magnetic disk; selecting, according to the calculated height deviation of the upper surface, a spacer ring having a thickness that reduces the height deviation from the two or more spacer rings; measuring the thickness of the selected spacer ring and calculating the thickness deviation from a predetermined design center value; laminating the selected spacer ring on the first magnetic disk; as well as For the second and subsequent disks and spacer rings, the thickness measurement, calculation of the thickness deviation from the predetermined design center value, stacking, calculation of the height deviation of the disk upper surface, and selection of the spacer rings are repeated, and more than 10 disks and more than 9 spacer rings are stacked in sequence.

Images