Base and hard disk drive

Abstract

To provide a technology that makes it possible to improve sealability of a base while avoiding occurrences of blow holes in a pivot shaft.SOLUTION: A base 10 is a part of a housing of a hard disk drive. The base 10 includes a bottom plate portion 12, a pivot shaft 14, and a first adhesive 16. The bottom plate portion 12 includes a bottom plate upper surface 12a facing upward, a bottom plate lower surface 12b facing downward, and a through hole 12c extending from the bottom plate upper surface 12a toward the bottom plate lower surface 12b. The pivot shaft 14 includes a base outer surface 14a1 press-fitted into an inner surface 12c1 of the through hole facing inward in the through hole 12c. The first adhesive 16 is interposed between the inner surface 12c1 of the through hole and the base outer surface 14a1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a base and a hard disk drive. [Background technology]

[0002] Conventionally, it has been known to prepare a base and a pivot shaft as separate members, and to fix the pivot shaft to the base (for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-322393 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-77237 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, demand for near-line type hard disk drives has increased, and there is a growing trend toward higher capacity and lower power consumption of hard disk drives. In such hard disk drives, it is becoming common to fill the internal space of the housing with helium gas.

[0005] Patent Document 1 discloses a technique for fixing a pivot shaft to a base member. Patent Document 2 discloses a technique for fitting and fixing the base of a pivot bearing into a hole in a casing base. However, with the techniques described in Patent Documents 1 and 2, if the internal space of the housing is filled with a gas (e.g., helium gas) that is less dense than air, there is a risk that this gas may leak into the external space through the gap between the pivot shaft and the base member.

[0006] To ensure the sealing of the housing and prevent leakage of helium gas, a base integrally formed with a pivot shaft is sometimes prepared by casting. However, because the pivot shaft is a member whose axial length is longer than its radial length, casting the base is prone to producing blowholes at its axial tip.

[0007] As demand for even higher capacity in hard disk drives increases in the future, it is expected that the height of the housing will increase. As the height of the housing increases, the length of the pivot shaft will also increase, making the tip of the pivot shaft more susceptible to blowholes.

[0008] The present invention has been made in view of the above-mentioned problems, and its object is to provide a technology that can prevent the occurrence of blowholes in a pivot shaft and improve the sealing performance of the base. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the base of the present invention is a base that forms part of the housing of a hard disk drive device, and comprises a bottom plate portion having an upper bottom plate surface facing upward, a lower bottom plate surface facing downward, and a hole extending from the upper bottom plate surface toward the lower bottom plate surface, a pivot shaft having a base outer surface that is pressed into the inner hole surface facing inward in the hole, and a first adhesive interposed between the inner hole surface and the base outer surface. [Effects of the Invention]

[0010] According to the base of the present invention, it is possible to improve the sealing performance of the base while avoiding the occurrence of blowholes in the pivot shaft. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an example of a hard disk drive device according to a first embodiment. [Figure 2] 2 is a partial cross-sectional view showing an example of a spindle motor used in the hard disk drive device of FIG. 1. FIG. [Figure 3] 2 is a partial cross-sectional view showing an example of a base used in the hard disk drive device of FIG. 1. FIG. [Figure 4] FIG. 4 is a partially enlarged view showing a part of FIG. 3. [Figure 5] 2 is a step chart showing an example of a method for manufacturing a base used in the hard disk drive device of FIG. 1. [Figure 6] FIG. 10 is a partially enlarged view showing a base according to a second embodiment. [Figure 7] 4 is a partial cross-sectional view showing a modified example of the base shown in FIG. 3. FIG. [Figure 8] 8 is a partial cross-sectional view showing a modified example of the base shown in FIG. 7. [Figure 9] FIG. 10 is a partially enlarged view showing a base according to a third embodiment. [Figure 10] FIG. 10 is a partially enlarged view showing a part of FIG. 9. [Figure 11] FIG. 10 is a partially enlarged view showing a base according to a fourth embodiment. [Figure 12] FIG. 11 is a partially enlarged view showing a base according to a fifth embodiment. [Figure 13] FIG. 10 is a partial cross-sectional view showing a base according to another modified example 1. [Figure 14] FIG. 10 is a partial cross-sectional view showing a base according to another modified example 2. [Figure 15] FIG. 10 is a partial cross-sectional view showing a base according to another modified example 3. [Figure 16] FIG. 10 is a partial cross-sectional view showing a base according to another modified example 4. [Figure 17] FIG. 13 is a partial cross-sectional view showing a base according to another modified example 5. [Figure 18] FIG. 13 is a partial cross-sectional view showing a base according to another modified example 6. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate.

[0013] First Embodiment Fig. 1 is a perspective view showing an example of a hard disk drive device 1 according to a first embodiment. Fig. 2 is a partial cross-sectional view showing an example of a spindle motor 50 used in the hard disk drive device 1 of Fig. 1. Fig. 3 is a partial cross-sectional view showing an example of a base 10 used in the hard disk drive device 1 of Fig. 1. Fig. 4 is a partial enlarged view showing an enlarged portion of Fig. 3.

[0014] Hereinafter, the direction parallel to the central axis C1 of the motor shaft 51 (FIG. 2) and the central axis C2 of the pivot shaft 14 (FIG. 3) will be referred to as the axial direction. The directions perpendicular to these axial directions will be referred to as the radial direction. The directions around the central axis C1 of the motor shaft 51 and the central axis C2 of the pivot shaft 14 will be referred to as the circumferential direction. For convenience of explanation, the axial direction will be referred to as the up-down direction, and the side of the bottom plate portion 12 of the base 10 relative to the motor shaft 51 and the pivot shaft 14 will be referred to as the bottom, and the opposite will be referred to as the up-down direction. Note that this up-down direction does not necessarily refer to the vertical direction. Therefore, depending on the installation location or orientation of the hard disk drive device 1, the up-down direction can be the horizontal direction, the vertical direction, or other directions.

[0015] (Hard Disk Drive 1) As shown in FIG. 1, the hard disk drive device 1 includes a housing 30, a spindle motor 50, a recording disk 60, an access unit 70, a voice coil motor 72, and a connector 74.

[0016] The housing 30 has a base 10 and a cover 40 attached to the base 10. The cover 40 is a plate-like member that closes the open surface of the base 10. The cover 40 is fastened to the base 10 using male screws 80. A sealing means (not shown) is provided between the cover 40 and the base 10, so that the cover 40, together with the base 10, forms the housing 30 having a sealed internal space.

[0017] The internal space of the housing 30 is filled with helium gas, which is a gas with a lower density than air. The internal space may be filled with, for example, nitrogen gas or a mixture of helium and nitrogen. The internal space may also be filled with other gases with a lower density than air. The internal space may also contain air. The internal space contains a spindle motor 50, a recording disk 60, an access unit 70, a voice coil motor 72, and a connector 74.

[0018] A plurality of recording disks 60 are provided and supported by the rotor 55 of the rotating part 50b of the spindle motor 50 so that the disk surfaces face each other. A gap is formed between each of the recording disks 60.

[0019] The access unit 70 is supported by the pivot shaft 14, and records data on the recording disk 60 and reads data recorded on the recording disk 60. Specifically, the access unit 70 has a bearing device 70a, a swing arm 70c, and a magnetic head 70d.

[0020] The bearing device 70a is attached to a pivot shaft 14 provided on the bottom plate portion 12 of the base 10, and swingably supports a plurality of swing arms 70c arranged in the gaps between the respective recording disks 60. A magnetic head 70d is provided at the tip of each swing arm 70c. The magnetic head 70d is a member that applies magnetism to the recording disks 60 and reads magnetism from the recording disks 60. The voice coil motor 72 is electrically connected to a printed circuit board (not shown) via a connector 74. The voice coil motor 72 supplies driving force to the swing arms 70c, thereby positioning the magnetic heads 70d relative to the recording disks 60.

[0021] When the rotor 55 of the spindle motor 50 rotates, the recording disk 60 also rotates. In this state, when the swing arm 70c swings, the magnetic head 70d moves over the rotating recording disk 60. The magnetic head 70d then applies magnetism to the recording disk 60 and reads magnetism from the recording disk 60. In this way, the magnetic head 70d records data on the recording disk 60 and reads data recorded on the recording disk 60.

[0022] (Spindle motor 50) The spindle motor 50 is used in the hard disk drive 1. The spindle motor 50 has a stationary part 50a supported by the base 10 and a rotating part 50b that rotates relative to the stationary part 50a. As shown in FIGS. 1 and 2, the stationary part 50a has a region of the bottom plate part 12 of the base 10, a motor shaft 51, a bearing member 52, a coil 53, and a stator core 54. The rotating part 50b has a rotor 55 and a rotor magnet 55a.

[0023] The motor shaft 51 is a cylindrical metal part, and as shown in FIG. 2, is fixed to one area of ​​the bottom plate portion 12 by press-fitting or the like. The motor shaft 51 has a threaded hole 82a at its upper end. The threaded hole 82a receives a male screw 80a (FIG. 1). The male screw 80a screws into the female screw formed in the threaded hole 82a, thereby fastening the cover 40 to the motor shaft 51.

[0024] A pair of conical bearing members 52 are fixed to the outer peripheral surface of the motor shaft 51, and a rotor 55 is rotatably supported by the pair of bearing members 52. The motor shaft 51 is inserted radially inside the rotor 55, and the rotor 55 faces the motor shaft 51 and the pair of bearing members 52 with a small gap between them. Lubricating oil (not shown) is filled in the small gap between the rotor 55 and the pair of bearing members 52, forming a so-called fluid dynamic bearing. A plurality of recording disks 60 are installed radially outside the rotor 55 (see FIG. 1).

[0025] 2, rotor magnet 55a is disposed on rotor 55. Rotor magnet 55a is a cylindrical member that is magnetized so that portions adjacent to SNSN... along the circumferential direction have alternate polarities. Rotor magnet 55a is attached to the inner surface of rotor 55 over the entire circumference.

[0026] A stator core 54 is fixed to the bottom plate portion 12. The stator core 54 is made by laminating multiple thin sheets of soft magnetic material (e.g., electromagnetic steel sheets) in the axial direction, has a ring shape, and is provided with multiple pole teeth that protrude radially outward. The multiple pole teeth are provided at equal intervals along the circumferential direction, and a coil 53 is wound around each of them. The inner peripheral surface of the rotor magnet 55a faces the outer peripheral surfaces of the pole teeth of the stator core 54 with a gap therebetween.

[0027] By passing a current through the coil 53 and switching the polarity, the magnetic attraction and repulsion forces generated between the rotor magnet 55a and the pole teeth of the stator core 54 are switched. As a result, the rotor 55 rotates around the motor shaft 51.

[0028] As the rotor 55 rotates at high speed, the lubricating oil filled in the minute gap between the pair of bearing members 52 and the rotor 55 is pressurized by dynamic pressure generating grooves (not shown). As a result, dynamic pressure is generated between the pair of bearing members 52 and the rotor 55, and the generated dynamic pressure causes the rotor 55 to rotate while being supported in a non-contact state relative to the motor shaft 51. In other words, the rotor 55 rotates while being supported in a non-contact state relative to the motor shaft 51.

[0029] (Base 10) As shown in FIGS. 3 and 4, the base 10 includes a base main body portion 11, a pivot shaft 14, and an adhesive (first adhesive) 16.

[0030] The base main body 11 has a bottom plate 12 and a side wall 13. As shown in Fig. 1, the base main body 11 has a box-like shape with a substantially rectangular parallelepiped and an open upper surface and a bottom, and is manufactured by die-casting a metal such as aluminum.

[0031] The bottom plate 12 is disposed below the base body 11 and has a rectangular plate shape with short and long sides. The bottom plate 12 may also have a square plate shape with four sides of equal length. As shown in FIG. 1, a side wall 13 is formed around the entire periphery of the bottom plate 12, extending in a direction perpendicular to the bottom plate 12 (i.e., upward). The side wall 13 has a side wall upper surface 13a facing upward.

[0032] 1, the side wall portion 13 has a plurality of screw holes 82 on the side wall upper surface 13a. The screw holes 82 accommodate male screws 80. The male screws 80 are threaded into the female threads formed in the screw holes 82, thereby fastening the cover 40 to the base main body portion 11.

[0033] As shown in FIGS. 3 and 4 , the bottom plate portion 12 has an upward-facing bottom plate upper surface 12a, a downward-facing bottom plate lower surface 12b, and a through-hole (hole) 12c extending from the bottom plate upper surface 12a to the bottom plate lower surface 12b. The through-hole 12c penetrates between the bottom plate upper surface 12a and the bottom plate lower surface 12b. The bottom plate portion 12 also has an upward-facing base mounting surface 12g in the area surrounding the through-hole 12c on the bottom plate upper surface 12a. The base mounting surface 12g is a partial area of ​​the bottom plate upper surface 12a and is formed slightly higher in the upward direction than the other areas of the bottom plate upper surface 12a. As will be described later, the base main body portion 11 is entirely coated with an electrodeposition coating film, but the base mounting surface 12g is an area from which the electrodeposition coating film has been removed by machining, such as cutting. The bearing device 70a of the access portion 70 is placed on the base mounting surface 12g.

[0034] 4, the bottom plate portion 12 has an upper tapered surface 12tu that extends inward and downward from an inner end 12a2 of the bottom plate upper surface 12a, i.e., the inner end 12a2 of the base mounting surface 12g. The upper tapered surface 12tu terminates at an upper edge 12c2 of a through-hole, which will be described later.

[0035] 3 and 4, through hole 12c has a through hole inner surface (hole inner surface) 12c1 formed in a ring shape around a central axis (not shown) extending in the vertical direction, a through hole upper edge 12c2 which is the upper end point of through hole inner surface 12c1, and a through hole lower edge 12c3 which is the lower end point of through hole inner surface 12c1. Through hole inner surface 12c1 is the surface facing inward in through hole 12c and extends in the vertical direction. Through hole 12c is a space defined by through hole inner surface 12c1, through hole upper edge 12c2, and through hole lower edge 12c3.

[0036] The bottom plate portion 12 has a lower tapered surface 12tb that starts at the lower edge 12c3 of the through hole and extends downward and outward, tapering to an inner end 12b1 of the bottom plate lower surface 12b.

[0037] A circumferential groove 12h recessed radially outward is formed at any position in the vertical direction on the through-hole inner surface 12c1. The circumferential groove 12h is formed in an annular shape around the central axis of the through-hole 12c. Note that the circumferential groove 12h does not necessarily have to be formed on the through-hole inner surface 12c1.

[0038] As shown in FIG. 3, the pivot shaft 14 has a base 14a extending vertically on the lower side, i.e., the side of the bottom plate 12, and a main body 14b extending vertically above the base 14a. The pivot shaft 14 is a cylindrical metal component manufactured by cutting a desired material such as aluminum or stainless steel (SUS). The manufacturing method of the pivot shaft 14 is not limited to cutting, and the pivot shaft 14 may be manufactured by casting, forging, or other methods. The pivot shaft 14 has a threaded hole 82b at the upper end of the main body 14b. The threaded hole 82b receives a male screw 80b (FIG. 1). The male screw 80b threads into the female screw formed in the threaded hole 82b, thereby fastening the cover 40 to the pivot shaft 14. The main body portion 14b has a main body portion outer surface 14b1 facing radially outward, and the bearing device 70a is attached to the main body portion outer surface 14b1 (FIG. 1).

[0039] The base 14a has a base lower surface 14a2 facing downward and a base outer surface 14a1 facing radially outward. The outer diameter R2 of the base outer surface 14a1 is the same as or approximately the same as the outer diameter R1 of the main body outer surface 14b1. The outer diameter R2 of the base outer surface 14a1 is slightly larger than the inner diameter (not shown) of the through-hole inner surface 12c1, so that the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, and the pivot shaft 14 is fixed to the base main body 11.

[0040] As shown in FIG. 4, the base 14a has a shaft tapered surface (tapered surface) 14a7 in a distal end region 14a4 of the base outer surface 14a1 in the press-fitting direction P into the through-hole inner surface 12c1. The shaft tapered surface 14a7 is formed so that the distance between the distal end region 14a4 and the through-hole inner surface 12c1 increases from a base end 14a5 of the distal end region 14a4 toward a distal end 14a6. As shown in FIG. 3, in this embodiment, the press-fitting direction P is from top to bottom, and the distal end region 14a4 of the base outer surface 14a1 is a lower region of the base outer surface 14a1. The position of the proximal end 14a5 on the base outer surface 14a1 may be changed as appropriate depending on the press-fit length of the base outer surface 14a1 (the length of the portion of the base outer surface 14a1 that contacts the through-hole inner surface 12c1). The distal end 14a6 on the base outer surface 14a1 is set at a position corresponding to the base lower surface 14a2.

[0041] In this embodiment, the shaft tapered surface 14a7 has a straight portion 15a in its upper region and a curved portion 15b in its lower region. The straight portion 15a extends obliquely downward and radially inward from the base end 14a5. The curved portion 15b connects the straight portion 15a to the base lower surface 14a2 and has a convexly curved surface. For example, the straight portion 15a may have an inclination angle of 3° to 10° with respect to the central axis C2 of the pivot shaft 14. Note that the shaft tapered surface 14a7 does not necessarily have to have the curved portion 15b. In this case, the shaft tapered surface 14a7 may have another straight portion (not shown) connecting the straight portion 15a to the base lower surface 14a2. The other straight portion may have an inclination angle with respect to the central axis C2 that is larger than the inclination angle of the straight portion 15a. For example, the inclination angle may be 45°.

[0042] As shown in FIG. 4, a thin layer of adhesive (first adhesive) 16 is at least partially interposed between the through-hole inner surface 12c1 and the base outer surface 14a1 in the vertical direction. As shown in FIGS. 3 and 4, the adhesive 16 forms an adhesive pool in the circumferential groove 12h. This adhesive pool provides a wedge effect of the adhesive 16, firmly fixing the pivot shaft 14 to the through-hole 12c. Examples of materials for the adhesive 16 include thermosetting epoxy resin and acrylic resin. Furthermore, it is preferable that the viscosity of the adhesive 16 be 7 Pa·s or less, as this is expected to allow the adhesive 16 to penetrate fine gaps.

[0043] 3 and 4, the base 10 includes a sealing adhesive (second adhesive) 18. The sealing adhesive 18 is applied to the base lower surface 14a2 and seals the gap between the through-hole inner surface 12c1 and the base outer surface 14a1. Examples of materials for the sealing adhesive 18 include thermosetting epoxy resin and acrylic resin.

[0044] (Base 10 manufacturing) FIG. 5 is a step chart showing an example of a method for manufacturing the base 10.

[0045] 1. Casting (S1) Molten aluminum is poured into a die-casting mold having a cavity corresponding to the shape of the base main body 11. After the molten aluminum cools and solidifies in the cavity, the die-casting mold is opened to remove the product, and the solidified portion remaining on the runner leading to the gate of the die-casting mold is cut off.

[0046] 2. E-coat (S2) The die-cast product in step S1 is immersed in a coating material, such as an epoxy resin, and an electric current is passed between the coating material and the product. This causes the coating material to adhere to the surface of the die-cast product. In this way, an electrodeposition coating film is formed on the surface of the product.

[0047] 3.Machining (S3) Next, in S2, the product on which the electrodeposition coating film has been formed is machined. Specifically, a portion of the bottom plate upper surface 12a of the electrodeposition coated product is cut to remove the electrodeposition coating film from that area, thereby forming the base mounting surface 12g. This completes the base main body 11.

[0048] 4. Apply adhesive and press-fit adhesion (S4) Next, the pivot shaft 14, which has been prepared in a separate process (e.g., cutting, casting, forging, etc.) from the base main body 11, is fixed to the base main body 11, which has been completed through steps S1 to S3, to complete the base 10. Specifically, adhesive 16 is applied to the vicinity of the upper edge 12c2 of the through hole 12c. Thereafter, downward force is applied to the upper end face of the main body 14b (around the screw hole 82b), so that the base 14a is pressed downward (press-fit direction P) into the through hole 12c. At this time, the adhesive 16 functions as a lubricant between the through hole inner surface 12c1 and the base outer surface 14a1. As a result, the base outer surface 14a1 is inserted, or press-fit, into the through hole inner surface 12c1 in an interference fit manner. Alternatively, the base portion 14a and the base main body portion 11 may be welded together after the base portion outer surface 14a1 is press-fitted into the through-hole inner surface 12c1.

[0049] As the base 14a advances downward through the through hole 12c, the adhesive 16 is scraped downward and at least partially spread thinly. As a result, the adhesive 16 is at least partially interposed between the through hole inner surface 12c1 and the base outer surface 14a1 in the vertical direction and hardens. That is, the adhesive 16 may be interposed partially or entirely between the through hole inner surface 12c1 and the base outer surface 14a1. Furthermore, if a circumferential groove 12h is formed in the through hole inner surface 12c1, the adhesive 16 forms an adhesive pool in the circumferential groove 12h. Note that "press-fit bonding" refers to fixing the base 14a to the through hole 12c by press-fitting and using the adhesive action of the adhesive 16. In S4, the main body outer surface 14b1 may be prepared in a roughly machined state, assuming that the main body outer surface 14b1 will be finished in S5, which will be described later.

[0050] 5. Finishing (S5) Finally, a finishing process is performed to improve the accuracy of the squareness between the main body outer surface 14b1 and the base mounting surface 12g. Here, "squareness" refers to the difference between the actual angle between the main body outer surface 14b1 and the base mounting surface 12g and a right angle (i.e., 90°). Improving the squareness accuracy means bringing this difference closer to zero. Specifically, after step S4, machining such as cutting is performed on the main body outer surface 14b1 and the base mounting surface 12g, thereby improving the squareness accuracy. By going through steps S1 to S5 in this manner, the base 10 is completed.

[0051] The hard disk drive device 1 is completed by assembling the motor shaft 51, bearing member 52, coil 53, stator core 54, rotor 55, access portion 70, etc. to the base 10 completed through the above-mentioned S1 to S5, and fastening the cover 40 to the base 10.

[0052] (Action, effect) Next, the functions and effects of the base 10 and the hard disk drive device 1 according to this embodiment will be described.

[0053] According to the base 10 of this embodiment, the base outer surface 14a1 of the pivot shaft 14 is press-fitted into the through-hole inner surface 12c1. That is, the pivot shaft 14 is manufactured separately from the base main body 11, and the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1. Therefore, the pivot shaft 14 is not cast integrally with the base main body 11, and no blowholes are formed at the upper end of the pivot shaft 14.

[0054] Since no blow holes are formed in the upper end of the pivot shaft 14, the rigidity of the upper end does not decrease. This stabilizes the movement of the access part 70 while the spindle motor 50 is running. Furthermore, since damage to the screw hole 82b is avoided when the screw 80b is threaded into the screw hole 82b of the pivot shaft 14, sufficient fastening strength can be ensured. Furthermore, since damage to the screw hole 82b is avoided, broken pieces can also be prevented from entering the interior of the housing 30.

[0055] Furthermore, the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, and the base outer surface 14a1 and the through-hole inner surface 12c1 are in close contact with each other. Furthermore, the adhesive 16 is interposed between the through-hole inner surface 12c1 and the base outer surface 14a1, which improves the sealing performance of the housing 30. This prevents gases with a lower density than air (e.g., helium gas) from leaking between the through-hole inner surface 12c1 and the base outer surface 14a1. Furthermore, the pivot shaft 14 can be firmly fixed to the base main body 11.

[0056] In the base 10 according to this embodiment, the sealing adhesive 18 is applied to the base lower surface 14a2 to seal between the through-hole inner surface 12c1 and the base outer surface 14a1, thereby firmly fixing the pivot shaft 14 to the base main body 11 and further improving the sealing performance of the housing 30.

[0057] According to the base 10 of this embodiment, the base 14a has a shaft tapered surface 14a7 in the tip region 14a4 of the base outer surface 14a1 in the press-fitting direction P (i.e., downward) into the through-hole inner surface 12c1. When the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, the pivot shaft 14 is brought close to the base main body 11 from above. At this time, even if the central axis C2 of the pivot shaft 14 is offset or inclined from the central axis C2 of the through-hole 12c (not shown), the shaft tapered surface 14a7 (straight portion 15a and curved portion 15b) of the pivot shaft 14 contacts the upper edge 12c2 of the through-hole, correcting the offset or inclination as the pivot shaft 14 moves downward. In this way, simply by moving the pivot shaft 14 downward, the base outer surface 14a1 can be press-fitted into the through-hole inner surface 12c1 with both central axes aligned or approximately aligned. Therefore, the base outer surface 14a1 can be easily press-fitted into the through-hole inner surface 12c1, and the assembly precision of the pivot shaft 14 can be improved.

[0058] In the hard disk drive device 1 according to this embodiment, a gas with a density lower than air, such as helium, is sealed in the housing 30. This reduces air resistance associated with the rotation of the recording disk 60. This allows the recording disk 60 to operate with high precision, making it possible to reduce the thickness of the recording disk 60, increase the number of disks, and meet the demand for higher capacity. On the other hand, gas with a density lower than air has a high probability of leaking to the outside from between the base outer surface 14a1 and the through-hole inner surface 12c1 due to its small atomic size. In this regard, in the hard disk drive device 1 according to this embodiment, the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, and an adhesive 16 is interposed between the base outer surface 14a1 and the through-hole inner surface 12c1. This improves the sealing performance of the housing 30 and suppresses helium leakage. Furthermore, in the hard disk drive device 1 according to this embodiment, when the sealing adhesive 18 is applied to the base lower surface 14a2, the sealing adhesive 18 seals the gap between the through-hole inner surface 12c1 and the base outer surface 14a1, further improving the sealing performance of the housing 30. This makes it possible to more reliably prevent helium leakage.

[0059] Second Embodiment Next, a base 102 according to a second embodiment of the present invention will be described.

[0060] Fig. 6 is a partially enlarged view showing the base 102 according to the second embodiment. The base 102 according to the second embodiment differs from the base 10 according to the first embodiment in the shape of the base portion 140. Note that although the circumferential groove 12h and the adhesive 16 are not shown in Fig. 6, the base 102 according to this embodiment may have the circumferential groove 12h and the adhesive 16.

[0061] 6, the base 140 of the pivot shaft 14 is cylindrical. The base outer surface 14a1 has an outer diameter R2 that is larger than the outer diameter R1 of the main body outer surface 14b1. This increases the circumferential contact area between the base outer surface 14a1 and the through-hole inner surface 12c1, allowing the pivot shaft 14 to be more firmly fixed to the base main body 112.

[0062] Furthermore, in the pivot shaft 14, the base 140 is located directly below the main body 14b. As such, the pivot shaft 14 is composed of only the base 140 and the main body 14b, and therefore the shape of the pivot shaft 14 is simple. This makes it possible to avoid complex manufacturing, improve the precision of the pivot shaft 14, and further reduce manufacturing costs.

[0063] The pivot shaft 14 also has a base upper surface 14a3 facing upward. The base upper surface 14a3 is a surface that connects an upper end 14a9 of the base outer surface 14a1 to a base 14b2 of the main body 14b. The base 14b2 of the main body 14b is the lower edge of the main body outer surface 14b1. The base upper surface 14a3 functions as a pivot mounting surface (mounting surface) 14a8 on which the bearing device 70a is placed. The pivot mounting surface 14a8 extends perpendicular to the up-down direction (i.e., the central axis C2) and is located above the bottom plate upper surface 12a.

[0064] In this way, since the pivot mounting surface 14a8 is formed on the pivot shaft 14 itself, it is possible to improve the accuracy of the perpendicularity between the main body outer surface 14b1 and the base upper surface 14a3 (i.e., the pivot mounting surface 14a8) in the process of manufacturing the pivot shaft 14. Therefore, it is possible to omit the finishing step (S5) required in the manufacturing process of the base 10 of the first embodiment.

[0065] <Modifications of the First and Second Embodiments> Next, a base 10m according to a modification of the first embodiment and a base 102m according to a modification of the second embodiment will be described.

[0066] Fig. 7 is a partial cross-sectional view showing a modified example of the base 10 shown in Fig. 3. Fig. 8 is a partial cross-sectional view showing a modified example of the base 102 shown in Fig. 7. The bases 10m and 102m according to this modified example differ from the base 10 according to the first embodiment and the base 102 according to the second embodiment in that a jig receiving surface 12d is provided. Note that although the circumferential groove 12h and the adhesive 16 are not shown in Figs. 7 and 8, the bases 10m and 102m according to this modified example may have the circumferential groove 12h and the adhesive 16.

[0067] As shown in FIGS. 7 and 8, the bottom plate portion 12 of the base main body portion 11m, 112m according to this modification has a jig receiving surface 12d on the bottom plate lower surface 12b. The jig receiving surface 12d faces downward in the same direction as the press-fitting direction P of the base outer surface 14a1 into the through-hole inner surface 12c1. The jig receiving surface 12d is a partial region of the bottom plate lower surface 12b and is formed higher than the other regions of the bottom plate lower surface 12b. The jig receiving surface 12d connects the through-hole lower edge 12c3 and the lower tapered surface 12tb. The jig receiving surface 12d is provided at least partially around the through hole 12c on the bottom plate lower surface 12b. Specifically, the jig receiving surface 12d is provided adjacent to the through hole 12c radially outward from the through hole 12c and is formed around the entire periphery of the through hole 12c. The jig receiving surface 12d may be formed partially around the through hole 12c (for example, at four locations symmetrical with respect to the central axis of the through hole 12c). The jig receiving surface 12d may be formed lower than other areas of the bottom plate lower surface 12b, or may be formed at approximately the same position (flush) as the bottom plate lower surface 12b in the up-down direction. The jig receiving surface 12d is the area from which the above-mentioned electrodeposition coating film has been removed.

[0068] By bringing a jig (not shown) into contact with the jig receiving surface 12d, the jig receives a downward force applied from the pivot shaft 14 to the base main body portions 11m, 112m when the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1. Therefore, the jig applies an upward force to the base main body portions 11m, 112m during the press-fitting. Therefore, downward displacement of the base main body portions 11m, 112m during the press-fitting is avoided, the base outer surface 14a1 can be easily press-fitted into the through-hole inner surface 12c1, and the assembly accuracy of the pivot shaft 14 can be improved.

[0069] Furthermore, in the bases 10m, 102m according to this modification, the jig receiving surface 12d is provided on the bottom plate lower surface 12b in a peripheral region adjacent to the through-hole 12c. Therefore, the jig can support the base main body 11m, 112m from below in the vicinity of the through-hole 12c. This more reliably prevents the base main body 11m, 112m from being displaced downward, further improving the assembly accuracy of the pivot shaft 14.

[0070] <Third embodiment> Next, a base 103 according to a third embodiment will be described.

[0071] Fig. 9 is a partially enlarged view showing a base 103 according to a third embodiment. Fig. 10 is a partially enlarged view showing a portion of Fig. 9. The base 103 according to the third embodiment differs from the base 102 according to the second embodiment in that the bottom plate portion 12 has a flange portion 12e and that a jig receiving surface 12d is provided on the bottom plate upper surface 12a. Note that although the circumferential groove 12h is not shown in Figs. 9 and 10, the base 103 according to this embodiment may have a circumferential groove 12h.

[0072] As shown in FIGS. 9 and 10 , the base 140a has a shaft tapered surface (tapered surface) 14a7 in a distal end region 14a4 of the base outer surface 14a1 in the press-fitting direction P into the through-hole inner surface 12c1. The shaft tapered surface 14a7 is formed so that the distance between the distal end region 14a4 and the through-hole inner surface 12c1 increases from a base end 14a5 of the distal end region 14a4 toward a distal end 14a6. As shown in FIG. 9 , in this embodiment, the press-fitting direction P is from bottom to top, and the distal end region 14a4 of the base outer surface 14a1 is an upper region of the base outer surface 14a1. The position of the base end 14a5 on the base outer surface 14a1 may be changed as appropriate depending on the press-fit length of the base outer surface 14a1. The distal end 14a6 on the base outer surface 14a1 is set at a position corresponding to the base upper surface 14a3.

[0073] In this embodiment, the shaft tapered surface 14a7 has a straight portion 15a in its lower region and a curved portion 15b in its upper region. The straight portion 15a extends obliquely upward and radially inward from the base end 14a5. The curved portion 15b connects the straight portion 15a to the base upper surface 14a3 and has a convexly curved surface. For example, the straight portion 15a may have an inclination angle of 3° to 10° with respect to the central axis C2 of the pivot shaft 14. Note that the shaft tapered surface 14a7 does not necessarily have to have the curved portion 15b. In this case, the shaft tapered surface 14a7 may have another straight portion (not shown) connecting the straight portion 15a to the base upper surface 14a3. The other straight portion may have an inclination angle with respect to the central axis C2 that is larger than the inclination angle of the straight portion 15a. For example, the inclination angle may be 45°.

[0074] When the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, the pivot shaft 14 is brought close to the base main body 113 from below. Even if the central axis C2 of the pivot shaft 14 is offset or inclined from the central axis C2 of the through-hole 12c (not shown), the shaft tapered surface 14a7 of the pivot shaft 14 contacts the lower edge 12c3 of the through-hole, correcting the offset or inclination as the pivot shaft 14 moves upward. Thus, simply by moving the pivot shaft 14 upward, the base outer surface 14a1 can be press-fitted into the through-hole inner surface 12c1 with the two central axes aligned or nearly aligned. This facilitates press-fitting the base outer surface 14a1 into the through-hole inner surface 12c1 and improves the assembly accuracy of the pivot shaft 14.

[0075] As shown in FIGS. 9 and 10 , the bottom plate 12 of the base main body 113 according to this embodiment has a flange 12e that extends inward (i.e., radially inward) of the through-hole 12c and covers the base upper surface 14a3 from above. The flange 12e has an upward-facing flange upper surface 12e1, a vertically extending flange inner surface 12e2, and a downward-facing flange lower surface 12e3. The flange upper surface 12e1 is a partial area of ​​the bottom plate upper surface 12a and is located slightly higher (upper) than the other areas of the bottom plate upper surface 12a. In this embodiment, the flange upper surface 12e1 functions as the base mounting surface 12g. The flange inner surface 12e2 defines a partial region (upper region) of the through hole 12c, but does not contact the main body outer surface 14b1 because it surrounds the main body outer surface 14b1 at a predetermined distance from the main body outer surface 14b1. The flange lower surface 12e3 faces the base upper surface 14a3. In this embodiment, the through hole 12c is a space defined by the through hole upper edge 12c2, the flange inner surface 12e2, the flange lower surface 12e3, the through hole inner surface 12c1, and the through hole lower edge 12c3.

[0076] As shown in FIG. 10 , in this embodiment, the adhesive 16 is thinly interposed at least partially between the through-hole inner surface 12c1 and the base outer surface 14a1 in the vertical direction, and thinly interposed radially between the flange lower surface 12e3 and the base upper surface 14a3. When the base outer surface 14a1 is press-fitted into the through-hole inner surface 12c1, the adhesive 16 is applied near the lower edge 12c3 of the through-hole 12c. Then, by applying an upward force to the base lower surface 14a2, the base 140a is pressed upward (press-fitting direction P) into the through-hole 12c. At this time, the adhesive 16 functions as a lubricant between the through-hole inner surface 12c1 and the base outer surface 14a1. As a result, the base outer surface 14a1 is inserted, or press-fitted, into the through-hole inner surface 12c1 in an interference fit manner. As base 140a moves upward in through-hole 12c, adhesive 16 is pushed upward and at least partially spread thinly. As a result, adhesive 16 is present not only between through-hole inner surface 12c1 and base outer surface 14a1, but also between flange lower surface 12e3 and base upper surface 14a3. Note that adhesive 16 may also be present between flange inner surface 12e2 and main body outer surface 14b1.

[0077] In this way, the base outer surface 14a1 can be press-fitted into the through-hole inner surface 12c1 while applying an upward force to the base lower surface 14a2, thereby preventing damage to the threaded hole 82b at the upper end of the main body 14b. Furthermore, by press-fitting the base outer surface 14a1 into the through-hole inner surface 12c1 until the base upper surface 14a3 abuts against the flange lower surface 12e3, variation in the length of the main body 14b protruding upward from the flange upper surface 12e1 can be reduced between products. This improves assembly accuracy when assembling the bearing device 70a to the pivot shaft 14. When the base upper surface 14a3 abuts against the flange lower surface 12e3, the electrodeposition coating film is removed from the flange lower surface 12e3 by cutting or the like. When base outer surface 14a1 is press-fitted into through-hole inner surface 12c1, base upper surface 14a3 does not have to abut against flange lower surface 12e3. In this case, the electrodeposition coating film on flange lower surface 12e3 is not removed.

[0078] 9 and 10, the bottom plate 12 of the base main body 113 according to this embodiment has a jig receiving surface 12d on the bottom plate upper surface 12a. The jig receiving surface 12d faces in the same direction as the press-fitting direction P of the base outer surface 14a1 into the through-hole inner surface 12c1, i.e., faces upward. The jig receiving surface 12d is provided at least partially around the through-hole 12c on the bottom plate upper surface 12a. Specifically, the jig receiving surface 12d is provided in a region radially outward of a flange upper surface 12e1 (i.e., a base mounting surface 12g), which is a region of the bottom plate upper surface 12a.

[0079] By contacting a jig (not shown) with the jig receiving surface 12d, upward displacement of the base main body portion 113 is avoided when the base outer surface 14a1 is pressed into the through-hole inner surface 12c1, making it possible to easily press the base outer surface 14a1 into the through-hole inner surface 12c1 and improving the assembly accuracy of the pivot shaft 14.

[0080] <Fourth embodiment> Next, a base 104 according to a modification of the fourth embodiment will be described.

[0081] Fig. 11 is a partially enlarged view showing a base 104 according to the fourth embodiment. The base 104 according to the fourth embodiment differs from the base 103 according to the third embodiment in that a step portion 14c is provided. Note that although the circumferential groove 12h and adhesive 16 are not shown in Fig. 11, the base 104 according to this embodiment may have the circumferential groove 12h and adhesive 16.

[0082] As shown in FIG. 11, the pivot shaft 14 has a stepped portion 14c located between the base portion 140a and the main body portion 14b. The stepped portion 14c extends vertically and includes an outward-facing stepped portion outer surface 14c1 and an upward-facing stepped portion upper surface 14c3. The stepped portion upper surface 14c3 connects an upper end 14c2 of the stepped portion outer surface 14c1 to the base 14b2 of the main body portion 14b. The stepped portion outer surface 14c1 has an outer diameter R3 that is larger than the outer diameter R1 of the main body portion outer surface 14b1 but smaller than the outer diameter R2 of the base outer surface 14a1. The stepped portion upper surface 14c3 functions as a pivot mounting surface 14a8 on which the bearing device 70a is mounted. In this embodiment, the base upper surface 14a3 is a surface that connects the lower end of the stepped portion outer surface 14c1 and the upper end of the base outer surface 14a1 and faces upward. The bottom plate 12 of the base 104 according to this embodiment has a flange 12e that covers the base upper surface 14a3 from above and surrounds the stepped portion outer surface 14c1 at a predetermined distance.

[0083] In this way, since the pivot mounting surface 14a8 is formed on the pivot shaft 14 itself, it is possible to improve the accuracy of the perpendicularity between the main body outer surface 14b1 and the stepped portion upper surface 14c3 (i.e., the pivot mounting surface 14a8) in the process of manufacturing the pivot shaft 14. Therefore, it is possible to omit the finishing step (S5) required in the manufacturing process of the base 10 of the first embodiment.

[0084] Fifth Embodiment Next, a base 105 according to a modification of the fifth embodiment will be described.

[0085] Fig. 12 is a partially enlarged view showing a base 105 according to the fifth embodiment. The base 105 according to the fifth embodiment differs from the base 10 according to the first embodiment in that it is provided with a storage portion 12f and a protrusion 14d. Note that although the circumferential groove 12h and adhesive 16 are not shown in Fig. 12, the base 105 according to this embodiment may have the circumferential groove 12h and adhesive 16.

[0086] As shown in FIG. 12, the pivot shaft 14 has a protrusion 14d between the base 14a and the main body 14b that protrudes outward from the base outer surface 14a1 and the main body outer surface 14b1.

[0087] The protrusion 14d has a protrusion lower surface 14d1 facing downward, a protrusion upper surface 14d2 facing upward, and a protrusion outer surface 14d3 facing radially outward. The protrusion lower surface 14d1, the protrusion upper surface 14d2, and the protrusion outer surface 14d3 are surfaces that extend annularly around the central axis C2 of the pivot shaft 14. The protrusion outer surface 14d3 is a surface that extends vertically, i.e., perpendicular to the protrusion lower surface 14d1 and the protrusion upper surface 14d2. The protrusion upper surface 14d2 functions as a pivot mounting surface 14a8 on which the bearing device 70a is mounted. The outer diameter R4 of the protrusion outer surface 14d3 is larger than the outer diameter R2 of the base outer surface 14a1 and the outer diameter R1 of the main body outer surface 14b1.

[0088] 12, the bottom plate portion 12 has a housing portion 12f recessed downward from the bottom plate upper surface 12a and configured to house the protrusion 14d. The housing portion 12f is a region of the bottom plate portion 12, specifically, a region adjacent to and radially outward from the through-hole inner surface 12c1. The housing portion 12f has an inner wall surface 12f2 extending downward from the bottom plate upper surface 12a, and a bottom wall surface 12f1 extending radially inward from the lower end of the inner wall surface 12f2 to the inner end 12a2.

[0089] A through-hole inner surface 12c1 extends downward from the inner end of the bottom wall surface 12f1, i.e., from the inner end 12a2 of the bottom plate upper surface 12a. The bottom wall surface 12f1 is a part of the bottom plate upper surface 12a and functions as a support region 12a1 that supports the protrusion lower surface 14d1 from below. The inner wall surface 12f2 defines a partial region (upper region) of the through-hole 12c, but does not contact the protrusion outer surface 14d3 because it surrounds the protrusion 14d with a predetermined distance from the protrusion outer surface 14d3. In this embodiment, the through-hole 12c is a space defined by the through-hole upper edge 12c2, the inner wall surface 12f2, the bottom wall surface 12f1, the through-hole inner surface 12c1, and the through-hole lower edge 12c3.

[0090] In this embodiment, the bottom plate portion 12 does not necessarily have to have the accommodation portion 12f in one region thereof. In this case, the support region 12a1 is formed flush with the bottom plate upper surface 12a (not shown).

[0091] The base main body portion 115 in this embodiment supports the protrusion underside 14d1 from below at the support region 12a1, so that even if a downward load (for example, the weight of the access portion 70) is applied to the pivot shaft 14 after assembly is complete, the pivot shaft 14 will not come out downward from the base main body portion 115.

[0092] Furthermore, by press-fitting the base outer surface 14a1 into the through-hole inner surface 12c1 until the protrusion lower surface 14d1 abuts against the support region 12a1, it is possible to reduce variations in the length of the main body 14b that protrudes upward from the bottom plate upper surface 12a between products. This improves the assembly accuracy when assembling the bearing device 70a to the pivot shaft 14. When the protrusion lower surface 14d1 abuts against the support region 12a1, the electrodeposition coating film is removed from the support region 12a1 by cutting or the like.

[0093] Furthermore, by accommodating the protruding portion 14d in the accommodating portion 12f, the length of the main body portion 14b can be maintained even when the protruding portion 14d is provided.

[0094] Next, other modifications will be described.

[0095] <Other Modifications 1 and 2> Fig. 13 is a partial cross-sectional view showing a base 106 according to another modified example 1. Fig. 14 is a partial cross-sectional view showing a base 107 according to another modified example 2. The bases 106 and 107 according to other modified examples 1 and 2 differ from the base 10 according to the first embodiment and the base 102 according to the second embodiment, respectively, in that they do not have a through hole 12c but have a blind hole 12s.

[0096] As shown in FIGS. 13 and 14 , the bases 106 and 107 according to the first and second modifications each have a blind hole (hole) 12s extending from the bottom plate upper surface 12a toward the bottom plate lower surface 12b. The blind hole 12s is recessed downward from the bottom plate upper surface 12a and terminates just before the bottom plate lower surface 12b. The blind hole 12s has a blind hole inner surface (hole inner surface) 12s1 extending downward from the bottom plate upper surface 12a and a blind hole bottom surface 12s2 facing upward at the lower end of the blind hole inner surface 12s1. When the base outer surface 14a1 is press-fitted into the blind hole inner surface 12s1, a gap G is formed between the base lower surface 14a2 and the blind hole bottom surface 12s2.

[0097] As shown in FIGS. 13 and 14 , the bases 106 and 107 have a jig receiving surface 12d on the bottom plate lower surface 12b. The jig receiving surface 12d may be provided at least partially around the blind hole 12s on the bottom plate lower surface 12b. More specifically, the jig receiving surface 12d may be provided at least partially around (radially outward from) an imaginary outline (not shown) of the blind hole 12s drawn on the bottom plate lower surface 12b when the bases 106 and 107 are viewed from below. The jig receiving surface 12d may also be provided below the bottom plate lower surface 12b. More specifically, the jig receiving surface 12d may be provided at a position on the bottom plate lower surface 12b that overlaps with the blind hole bottom surface 12s2 in the axial direction (i.e., radially inward from the imaginary outline (not shown)). The jig receiving surface 12d may also be provided on the bottom plate lower surface 12b on the imaginary outline.

[0098] According to the bases 106 and 107 of this modification, the sealing performance of the housing 30 can be improved, and leakage of helium gas or the like filled in the internal space of the housing 30 can be reliably prevented.

[0099] <Other variations 3 to 6> Fig. 15 is a partial cross-sectional view showing a base 108 according to another modified example 3. Fig. 16 is a partial cross-sectional view showing a base 109 according to another modified example 4. Fig. 17 is a partial cross-sectional view showing a base 110 according to another modified example 5. Fig. 18 is a partial cross-sectional view showing a base 111 according to another modified example 6.

[0100] The bases 108, 109, 110, and 111 according to the other modified examples 3 to 6 differ from the bases 106 and 107 according to the other modified examples 1 and 2, respectively, in that holes for releasing air and adhesive 16 are provided.

[0101] As shown in FIG. 15 , the base 108 according to Variation 3 has a through-hole 12u in the base main body 118 that penetrates between the blind hole bottom surface 12s2 and the bottom plate lower surface 12b. The through-hole 12u connects the gap G to the space below the base main body 118. With the base outer surface 14a1 press-fitted into the blind hole inner surface 12s1, a thin layer of adhesive 16 is at least partially interposed between the blind hole inner surface 12s1 and the base outer surface 14a1 (not shown). The adhesive 16 is also contained in the gap G and the through-hole 12u.

[0102] As shown in FIG. 16 , a base 109 according to Modification 4 has a base 140 with a cutout hole 17 formed by cutting out a portion of the base outer surface 14a1 in the vertical direction and penetrating between the base upper surface 14a3 and the base lower surface 14a2. The cutout hole 17 connects the gap G to the space above the base 140. When the base outer surface 14a1 is press-fitted into the blind hole inner surface 12s1, an adhesive 16 is at least partially interposed between the blind hole inner surface 12s1 and the base outer surface 14a1 (not shown). The adhesive 16 is also contained in the gap G and a portion of the cutout hole 17.

[0103] As shown in FIG. 17 , the base 110 according to Variation 5 has a cutout 17 in the base main body 120, which cuts out a portion of the blind hole inner surface 12s1 in the vertical direction from the bottom plate upper surface 12a, i.e., the base mounting surface 12g, to the blind hole bottom surface 12s2. The cutout 17 connects the gap G to the space above the base main body 120. When the base outer surface 14a1 is press-fitted into the blind hole inner surface 12s1, adhesive 16 is at least partially interposed between the blind hole inner surface 12s1 and the base outer surface 14a1 (not shown). The adhesive 16 is also contained in the gap G and a portion of the cutout 17.

[0104] As shown in FIG. 18 , the base 111 according to Variation 6 has a through hole 19 that penetrates between the base upper surface 14a3 and the base lower surface 14a2 at a position in the base 140 that is spaced radially inward from the base outer surface 14a1. The through hole 19 connects the gap G to the space above the base 140. When the base outer surface 14a1 is press-fitted into the blind hole inner surface 12s1, the adhesive 16 is at least partially interposed between the blind hole inner surface 12s1 and the base outer surface 14a1 (not shown). The adhesive 16 is also contained in the gap G and part of the through hole 19.

[0105] In the above embodiment, the following aspects are disclosed.

[0106] (Aspect 1) In the above embodiment, the bases 10, 10m, 102, 102m, 103, 104, 105, 106, 107, 108, 109, 110, and 111 form part of the housing 30 of the hard disk drive device 1, and include a bottom plate portion 12 having an upward-facing bottom plate upper surface 12a, a downward-facing bottom plate lower surface 12b, and holes 12c and 12s extending from the bottom plate upper surface 12a toward the bottom plate lower surface 12b, a pivot shaft 14 having a base outer surface 14a1 that is pressed into inward-facing hole inner surfaces 12c1 and 12s1 in the hole, and an adhesive 16 interposed between the hole inner surfaces 12c1 and 12s1 and the base outer surface 14a1.

[0107] (Aspect 2) In aspect 1, hole 12c is a through hole 12c that penetrates between bottom plate upper surface 12a and bottom plate lower surface 12b, and pivot shaft 14 has a base lower surface 14a2 facing downward and is provided with sealing adhesive 18 that is applied to base lower surface 14a2 and seals between through hole inner surface 12c1 and base outer surface 14a1.

[0108] (Aspect 3) In aspect 1 or 2, the holes 12c, 12s are through holes 12c that penetrate between the bottom plate upper surface 12a and the bottom plate lower surface 12b, or blind holes 12s that terminate just before the bottom plate lower surface 12b, and the pivot shaft 14 has a shaft tapered surface 14a7 in the tip region 14a4 of the base outer surface 14a1 in the press-fitting direction P into the through hole 12c or blind hole 12s, where the distance between the tip region 14a4 and the through hole inner surface 12c1 or blind hole inner surface 12s1 increases from the base end 14a5 of the tip region 14a4 toward the tip 14a6.

[0109] (Aspect 4) In any of aspects 1 to 3, holes 12c, 12s are through holes 12c that penetrate between the bottom plate upper surface 12a and the bottom plate lower surface 12b, or blind holes 12s that terminate just before the bottom plate lower surface 12b, and pivot shaft 14 has a main body outer surface 14b1 that extends in the vertical direction above base outer surface 14a1, and base outer surface 14a1 is formed with an outer diameter R2 that is larger than the outer diameter R1 of main body outer surface 14b1.

[0110] (Aspect 5) In any of aspects 1 to 4, the hole 12c is a through hole 12c that penetrates between the bottom plate upper surface 12a and the bottom plate lower surface 12b, the pivot shaft 14 connects the base outer surface 14a1 and the main body outer surface 14b1 and has a base upper surface 14a3 that faces upward, and the bottom plate portion 12 has a flange portion 12e that extends inward of the through hole 12c and covers the base upper surface 14a3 from above.

[0111] (Aspect 6) In any of the first to fifth embodiments, the bottom plate portion 12 has a jig receiving surface 12d on the bottom plate upper surface 12a or the bottom plate lower surface 12b, which faces in the same direction as the base outer surface 14a1 is press-fitted into the through hole 12c or the blind hole 12s.

[0112] (Aspect 7) In any of aspects 1 to 6, the hole 12c is a through hole 12c that penetrates between the bottom plate upper surface 12a and the bottom plate lower surface 12b, and the jig receiving surface 12d is provided at least partially around the through hole 12c on the bottom plate upper surface 12a or the bottom plate lower surface 12b.

[0113] (Aspect 8) In any of the first to sixth embodiments, the hole 12s is a blind hole 12s that terminates just before the bottom plate lower surface 12b, and the jig receiving surface 12d is at least partially provided on the bottom plate lower surface 12b.

[0114] (Aspect 9) In any of aspects 1 to 8, holes 12c, 12s are through holes 12c that penetrate between bottom plate upper surface 12a and bottom plate lower surface 12b, or blind holes 12s that terminate just before bottom plate lower surface 12b, and pivot shaft 14 has main body outer surface 14b1 that extends in the vertical direction above base outer surface 14a1, and base mounting surface 12g or pivot mounting surface 14a8 that extends perpendicular to the vertical direction and is located above bottom plate upper surface 12a.

[0115] (Aspect 10) In any of aspects 1 to 9, holes 12c, 12s are through holes 12c that penetrate between bottom plate upper surface 12a and bottom plate lower surface 12b, or blind holes 12s that terminate just before bottom plate lower surface 12b, base outer surface 14a1 is formed with an outer diameter R2 that is larger than the outer diameter R1 of main body outer surface 14b1, and includes base upper surface 14a3 that connects base outer surface 14a1 and main body outer surface 14b1 and faces upward, and pivot mounting surface 14a8 is base upper surface 14a3.

[0116] (Aspect 11) In any of the first to tenth embodiments, the hole 12c is a through-hole 12c that penetrates between the bottom plate upper surface 12a and the bottom plate lower surface 12b. The pivot shaft 14 has a stepped portion outer surface 14c1 extending vertically between the base portion outer surface 14a1 and the main body portion outer surface 14b1, a stepped portion upper surface 14c3 connecting the stepped portion outer surface 14c1 and the main body portion outer surface 14b1 and facing upward, and a base portion upper surface 14a3 connecting the stepped portion outer surface 14c1 and the base portion outer surface 14a1 and facing upward. The stepped portion outer surface 14c1 has an outer diameter R3 that is larger than the outer diameter R1 of the main body portion outer surface 14b1 but smaller than the outer diameter R2 of the base portion outer surface 14a1. The pivot mounting surface 14a8 is the stepped portion upper surface 14c3. The bottom plate portion 12 has a flange portion 12e that extends inward of the through-hole 12c, covers the base portion upper surface 14a3 from above, and surrounds the stepped portion outer surface 14c1.

[0117] (Aspect 12) In any of the first to ninth embodiments, the holes 12c and 12s are through-holes 12c that penetrate between the bottom plate upper surface 12a and the bottom plate lower surface 12b, or blind holes 12s that terminate just short of the bottom plate lower surface 12b. The pivot shaft 14 has a protrusion 14d that protrudes outward from the base outer surface 14a1 and the main body outer surface 14b1 between the base outer surface 14a1 and the main body outer surface 14b1. The protrusion 14d includes a protrusion lower surface 14d1 facing downward and a protrusion upper surface 14d2 facing upward. The bottom plate upper surface 12a has a support region 12a1 that supports the protrusion lower surface 14d1 from below. The pivot mounting surface 14a8 is the protrusion upper surface 14d2.

[0118] (Aspect 13) In the twelfth aspect, the bottom plate portion 12 has a receiving portion 12f that is recessed downward from the bottom plate upper surface 12a and receives the protrusion 14d. The support region 12a1 is a bottom wall surface 12f1 of the receiving portion 12f.

[0119] (Aspect 14) In the above embodiment, the hard disk drive device 1 comprises a base according to any one of aspects 1 to 13, a cover 40 attached to the base and forming a housing 30 together with the base, a spindle motor 50 arranged inside the housing 30 and supported by the base, a recording disk 60 arranged inside the housing 30 and rotated by the spindle motor 50, and an access unit 70 supported by a pivot shaft 14 inside the housing 30 and configured to record data on the recording disk 60 and read data recorded on the recording disk.

[0120] (Aspect 15) In the fourteenth embodiment, the housing 30 is filled with a gas having a density lower than that of air.

[0121] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the bases 10, 10m, 102, 102m, 103, 104, 105, 106, 107, 108, 109, 110, and 111 and the hard disk drive device 1 according to the above embodiments, but includes all aspects encompassed by the concept of the present invention and the scope of the claims. Furthermore, each configuration may be appropriately and selectively combined to achieve the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately modified depending on the specific aspects of the present invention.

[0122] For example, in the above embodiment, an example of the spindle motor 50 has been described in which the motor shaft 51 is a separate part from the base 10. However, the motor shaft 51 may be die-cast integrally with the base main body 11 as a component of the base 10.

[0123] In the above embodiment, an example of a spindle motor 50 has been described in which the motor shaft 51 is a component of the stationary part 50a. That is, an example has been described in which the motor shaft 51 is fixed to the base main body part 11 by press fitting or the like, and a pair of bearing members 52 is fixed to the outer circumferential surface of this motor shaft 51. However, the spindle motor may also have a motor shaft as a component of the rotating part 50b. That is, the spindle motor may be configured such that a bearing sleeve (not shown) is fixed to the base, and a rotor is fixed to the outer circumferential surface of the motor shaft rotatably supported by the bearing sleeve.

[0124] In the above embodiment, the base 14a and the base main body 11 are welded together with the adhesive 16 interposed between the base outer surface 14a1 and the through-hole inner surface 12c1. However, the base 14a and the base main body 11 may be welded together without the adhesive 16 interposed between the base outer surface 14a1 and the through-hole inner surface 12c1. [Explanation of symbols]

[0125] 1 hard disk drive device, 10, 10m, 102, 102m, 103, 104, 105 base, 12 bottom plate portion, 12a bottom plate upper surface, 12a1 support area, 12b bottom plate lower surface, 12c through hole (hole), 12c1 through hole inner surface (hole inner surface), 12d jig receiving surface, 12e flange portion, 12f accommodation portion, 12f1 bottom wall surface, 12g base mounting surface (mounting surface), 12s blind hole (hole), 12s1 blind hole inner surface (hole inner surface), 14 pivot shaft, 14a, 140, 140a base, 14a1 base outer surface, 14a2 base lower surface, 14a3 base upper surface, 14a4 tip area, 14a5 base end, 14a6 tip end, 14a7 shaft tapered surface (tapered surface), 14a8 pivot mounting surface (mounting surface), 14b main body, 14c step portion, 14c1 step portion outer surface, 14c3 step portion upper surface, 14d protrusion, 14d1 protrusion portion lower surface, 14d2 protrusion portion upper surface, 16 adhesive (first adhesive), 18 sealing adhesive (second adhesive), 30 housing, 40 cover, 50 spindle motor, 60 recording disk, 70 access portion, P press-fit direction, R1, R2, R3, R4 outer diameter

Claims

1. A base that is part of the housing of the hard disk drive, a bottom plate portion having an upper surface facing upward, a lower surface facing downward, and a hole extending from the upper surface toward the lower surface; a pivot shaft having a base outer surface that is press-fitted into the inner surface of the hole facing inward; a first adhesive interposed between the inner surface of the hole and the outer surface of the base; A base equipped with:

2. the hole is a through hole that penetrates between the upper surface of the bottom plate and the lower surface of the bottom plate, the pivot shaft has a base lower surface facing downward; a second adhesive applied to the lower surface of the base and sealing between the inner surface of the hole and the outer surface of the base; The base of claim 1 .

3. the hole is a through hole that passes through between the upper surface of the bottom plate and the lower surface of the bottom plate, or a blind hole that terminates just before the lower surface of the bottom plate, the pivot shaft has a tapered surface at a tip region of the outer surface of the base portion in a direction of press-fitting into the inner surface of the hole, the tapered surface having a distance from the base end of the tip region to the inner surface of the hole increasing from the base end to the tip of the tip region; The base of claim 1 .

4. the hole is a through hole that passes through between the upper surface of the bottom plate and the lower surface of the bottom plate, or a blind hole that terminates just before the lower surface of the bottom plate, the pivot shaft has a main body outer surface extending in the vertical direction above the base outer surface, The outer diameter of the base outer surface is larger than the outer diameter of the main body outer surface. The base of claim 1 .

5. the hole is a through hole that penetrates between the upper surface of the bottom plate and the lower surface of the bottom plate, the pivot shaft connects the base outer surface and the main body outer surface and has a base upper surface facing upward; The bottom plate portion has a flange portion that extends inwardly of the hole and covers the upper surface of the base portion from above. The base according to claim 4.

6. The bottom plate portion has a jig receiving surface on the bottom plate upper surface or the bottom plate lower surface, the jig receiving surface facing in the same direction as the press-fitting direction of the outer surface of the base portion into the inner surface of the hole. The base of claim 1 .

7. the hole is a through hole that penetrates between the upper surface of the bottom plate and the lower surface of the bottom plate, The jig receiving surface is provided at least partially around the hole on the upper surface of the bottom plate or the lower surface of the bottom plate. The base according to claim 6.

8. the hole is a blind hole that terminates just before the lower surface of the bottom plate, The jig receiving surface is at least partially provided on the lower surface of the bottom plate. The base according to claim 6.

9. the hole is a through hole that passes through between the upper surface of the bottom plate and the lower surface of the bottom plate, or a blind hole that terminates just before the lower surface of the bottom plate, The pivot shaft is a main body outer surface extending in the vertical direction above the base outer surface; a mounting surface extending perpendicular to the up-down direction and positioned above the top surface of the bottom plate; The base of claim 1 .

10. The outer diameter of the base portion outer surface is larger than the outer diameter of the main body portion outer surface, the pivot shaft connects the base outer surface and the main body outer surface and has a base upper surface facing upward; The mounting surface is the upper surface of the base.

10. The base of claim 9.

11. the hole is a through hole that penetrates between the upper surface of the bottom plate and the lower surface of the bottom plate, the pivot shaft has a stepped portion outer surface extending in the vertical direction between the base portion outer surface and the main body portion outer surface, a stepped portion upper surface connecting the stepped portion outer surface and the main body portion outer surface and facing upward, and a base portion upper surface connecting the stepped portion outer surface and the base portion outer surface and facing upward, the stepped portion outer surface is formed to have an outer diameter larger than an outer diameter of the main body portion outer surface and smaller than an outer diameter of the base portion outer surface, the mounting surface is an upper surface of the step portion, The bottom plate portion extends inwardly of the hole, covers the upper surface of the base portion from above, and has a flange portion that surrounds the outer surface of the step portion.

10. The base of claim 9.

12. the pivot shaft has a protrusion that protrudes outward from the base outer surface between the base outer surface and the main body outer surface, and that protrudes outward from the main body outer surface, the protrusion having a protrusion lower surface facing downward and a protrusion upper surface facing upward; the upper surface of the bottom plate has a support region that supports the lower surface of the protrusion from below, The mounting surface is an upper surface of the protrusion.

10. The base of claim 9.

13. the bottom plate portion has a receiving portion that is recessed downward from an upper surface of the bottom plate and receives the protrusion, The support area is a bottom wall surface of the storage section. The base of claim 12.

14. A base according to any one of claims 1 to 13; a cover attached to the base and forming the housing together with the base; a spindle motor disposed inside the housing and supported by the base; a recording disk disposed inside the housing and rotated by the spindle motor; an access unit supported by the pivot shaft inside the housing, for recording data on the recording disk and reading data recorded on the recording disk; A hard disk drive comprising:

15. 15. The hard disk drive device according to claim 14, wherein the housing is filled with a gas having a density lower than that of air.

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