JP2014192916A - Rotary apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain or enhance the coupling strength between members even if a fixed shaft type rotary apparatus is made thin.SOLUTION: A rotary apparatus 100 includes a rotating body on which a magnetic recording disk 8 is mounted, and a fixed body for supporting the rotating body rotatably. The fixed body includes a supporting protrusion 108 extending along the axis of rotation R of the rotating body, a shaft 26 surrounding the supporting protrusion 108 and fixed thereto, a top cover 2 covering the rotating body, and a shaft fixing screw 6 for fixing the top cover 2 to the shaft 26. The shaft fixing screw 6 enters a shaft fixing hole 152 formed in the supporting protrusion 108 along the axis of rotation R.

Description

  The present invention relates to a rotating device that rotates a recording disk.

  Disk drive devices such as hard disk drives are becoming smaller and larger in capacity, and are mounted on various electronic devices. In particular, the mounting of disk drive devices in portable electronic devices such as notebook computers and portable music playback devices is advancing.

  For example, Patent Document 1 and Patent Document 2 propose a motor in which a shaft is fixed to a base plate and a fluid dynamic bearing mechanism is adopted as a bearing.

JP 2009-162246 A JP 2010-127448 A

  In recent years, thinning of portable electronic devices has been remarkable, and accordingly, further thinning of disk drive devices has been demanded. As disk drive devices become thinner, the base plate must be thinner. Here, in the shaft fixed type disk drive device described in Patent Documents 1 and 2, since the shaft is inserted and fixed in the hole provided in the base plate, the coupling strength between the shaft and the base plate is reduced when the base plate is thinned. May decrease.

  Such a problem may occur not only in the disk drive device but also in other types of rotating equipment.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a shaft-fixed rotary device that can maintain or improve the coupling strength between members even if the thickness is reduced.

  One embodiment of the present invention relates to a rotating device. The rotating device includes a rotating body on which the recording disk is to be placed, and a fixed body that rotatably supports the rotating body. The fixed body includes an inner portion that extends along the rotation axis of the rotating body, an outer portion that surrounds the inner portion and is fixed to the inner portion, a cover that covers the rotating body, and a cover that faces the outer portion A coupling portion to be fixed. The coupling part enters a hole formed in the inner part along the rotation axis.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if it makes a shaft fixed type rotary apparatus thin, the joint strength between members can be maintained or improved.

Fig.1 (a)-(c) is a figure which shows the rotary equipment which concerns on embodiment. It is the sectional view on the AA line of Fig.1 (a). 3A and 3B are schematic diagrams for explaining the positional relationship between the edge-corresponding recess and the upper edge of the bypass communication hole. It is an enlarged view which expands and shows a part of FIG. It is sectional drawing which shows the shaft of the rotary apparatus which concerns on a 1st modification, and its periphery. FIG. 6 is an enlarged view of a portion surrounded by a broken line in FIG. 5. It is a fragmentary sectional view showing the important section of the rotating equipment concerning the 2nd modification. It is sectional drawing which shows the shaft of the rotary apparatus which concerns on a 3rd modification, and its periphery.

  Hereinafter, the same or equivalent components and members shown in the respective drawings are denoted by the same reference numerals, and repeated descriptions thereof are omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  The rotating device according to the embodiment is suitably used as a disk drive device such as a hard disk drive that mounts a magnetic recording disk and rotationally drives it, and in particular, the shaft is fixed to the base and the hub rotates relative to the shaft. It is suitably used as a shaft fixed type disk drive device.

Fig.1 (a)-(c) is a figure which shows the rotary apparatus 100 which concerns on embodiment. FIG. 1A is a top view of the rotating device 100. FIG. 1B is a side view of the rotating device 100. FIG. 1C is a top view of the rotating device 100 with the top cover 2 removed. The rotating device 100 includes a fixed body, a rotating body that rotates with respect to the fixed body, a magnetic recording disk 8 that is attached to the rotating body, and a data read / write unit 10. The fixed body includes a base 4, a shaft 26 fixed to the base 4, a housing 102 that supports the shaft 26, a top cover 2, six screws 20, and a shaft fixing screw 6. The rotating body includes a hub 28, a clamper 36, and the cover ring 12.
Hereinafter, the side on which the hub 28 is mounted on the base 4 will be described as the upper side.

  The magnetic recording disk 8 is a glass 2.5-inch magnetic recording disk having a diameter of 65 mm, and the diameter of the hole in the center is 20 mm and the thickness is 0.65 mm. The hub 28 carries one magnetic recording disk 8.

  The base 4 is formed by molding an aluminum alloy by die casting. The base 4 includes a bottom plate portion 4 a that forms the bottom portion of the rotating device 100, and an outer peripheral wall portion 4 b that is formed along the outer periphery of the bottom plate portion 4 a so as to surround the mounting area of the magnetic recording disk 8. Six screw holes 22 are provided in the upper surface 4c of the outer peripheral wall 4b. The base 4 may be formed by pressing from a steel plate or an aluminum plate.

  In order to prevent peeling of the surface of the base 4, the base 4 is subjected to a surface coating. The surface coating may be a coating with a resin material such as an epoxy resin. Alternatively, the surface coating may be a coating by plating a metal material such as nickel or chromium. In the embodiment, electroless nickel plating is applied to the surface of the base 4. Compared with coating with a resin material, the surface hardness can be increased and the friction coefficient can be decreased. Further, for example, when the magnetic recording disk 8 comes into contact with the surface of the base 4 during manufacturing, the possibility that the surface of the base 4 or the magnetic recording disk 8 is damaged can be reduced. In the embodiment, the coefficient of static friction of the surface of the base 4 is in the range of 0.1 to 0.6. The possibility that the base 4 and the magnetic recording disk 8 are damaged can be further reduced as compared with the case where the coefficient of static friction is 2 or more.

  The data read / write unit 10 includes a recording / reproducing head (not shown), a swing arm 14, a voice coil motor 16, and a pivot assembly 18. The recording / reproducing head is attached to the tip of the swing arm 14, records data on the magnetic recording disk 8, and reads data from the magnetic recording disk 8. The pivot assembly 18 supports the swing arm 14 so as to be swingable around the head rotation axis S with respect to the base 4. The voice coil motor 16 swings the swing arm 14 around the head rotation axis S and moves the recording / reproducing head to a desired position on the upper surface of the magnetic recording disk 8. The voice coil motor 16 and the pivot assembly 18 are configured using a known technique for controlling the position of the head.

  The top cover 2 covers the rotating body. The top cover 2 is fixed to the upper surface 4 c of the outer peripheral wall portion 4 b of the base 4 using six screws 20. The six screws 20 correspond to the six screw holes 22, respectively. In particular, the top cover 2 and the upper surface 4c of the outer peripheral wall 4b are fixed to each other so that no leakage occurs from the joint portion to the inside of the rotating device 100. Here, the inside of the rotating device 100 is specifically a clean space 24 surrounded by the bottom plate portion 4 a of the base 4, the outer peripheral wall portion 4 b of the base 4, and the top cover 2. This clean space 24 is designed so as to be sealed, that is, to prevent leak-in from the outside or leak-out to the outside. The clean space 24 is filled with clean air from which particles have been removed. Thereby, adhesion of foreign matters such as particles to the magnetic recording disk 8 is suppressed, and the operation reliability of the rotating device 100 is improved.

  The shaft 26 extends along the rotation axis of the hub 28. A shaft fixing screw hole 152 is provided on the upper end surface of the housing 102. The shaft fixing screw 6 passes through the top cover 2 and is screwed into the shaft fixing screw hole 152 to fix the top cover 2 to the shaft 26.

  Among the fixed shaft type rotating devices, according to the rotating device in which both ends of the shaft 26 are fixed to the chassis such as the base 4 and the top cover 2, the shock resistance and vibration resistance of the rotating device are improved. Can do.

FIG. 2 is a cross-sectional view taken along line AA in FIG. The cross section shown in FIG. 2 corresponds to a half cross section of the motor portion of the rotating device 100.
The rotating body includes a hub 28, a clamper 36, a cylindrical magnet 32, and the cover ring 12. The fixed body includes a base 4, a laminated core 40, a coil 42, a housing 102, a shaft 26, and a ring portion 104. A lubricant 92 is continuously interposed in a part of the gap between the rotating body and the fixed body.

  The hub 28 is formed by cutting or pressing a steel material such as SUS430 having soft magnetism, and is formed in a predetermined cup-like shape. In order to suppress peeling of the surface of the hub 28, a surface layer forming process such as electroless nickel plating may be performed on the surface of the hub 28. The hub 28 includes a shaft surrounding portion 28 j that surrounds the shaft 26, a hub protruding portion 28 g that is provided radially outside the shaft surrounding portion 28 j, and fits in the central hole 8 a of the magnetic recording disk 8, and a hub protruding portion And a mounting portion 28h provided on the radially outer side than 28g. The magnetic recording disk 8 is placed on a disk placement surface 28a which is the upper surface of the placement portion 28h. The magnetic recording disk 8 is fixed to the hub 28 by being sandwiched between the clamper 36 and the mounting portion 28h.

  The clamper 36 applies a downward force to the upper surface of the magnetic recording disk 8 and presses the magnetic recording disk 8 against the disk mounting surface 28a. The clamper 36 is engaged with the outer peripheral surface 28d of the hub protrusion 28g. The clamper 36 and the outer peripheral surface 28d of the hub protruding portion 28g may be coupled by mechanical coupling means such as screwing, caulking, press-fitting or the like, or magnetic coupling means using a magnetic attractive force.

  The clamper 36 is formed so that the upper surface 36a of the clamper 36 does not protrude upward beyond the upper surface 28e of the hub protruding portion 28g in a state where the clamper 36 applies a desired downward force to the magnetic recording disk 8.

  For example, when the clamper 36 and the outer peripheral surface 28d of the hub protrusion 28g are screwed together, a male screw is formed on the outer peripheral surface 28d of the hub protrusion 28g, and a corresponding female screw is formed on the inner peripheral surface 36b of the clamper 36. The In this case, the strength of the downward force that the clamper 36 applies to the upper surface of the magnetic recording disk 8 can be controlled relatively accurately by the strength of the screwing. The clamper 36 may be formed from a plurality of members, or may be an integral member.

  If burr due to processing is attached to the outer peripheral surface 28d of the hub protruding portion 28g, when the clamper 36 is screwed to the outer peripheral surface 28d, the clamper 36 may come into contact with the processing burr and peel off. . In order to remove such processed burrs in advance, the outer peripheral surface 28d of the hub protrusion 28g may be subjected to burrs removal processing.

  The cylindrical magnet 32 is bonded and fixed to a cylindrical inner peripheral surface 28 f corresponding to the inner cylindrical surface of the hub 28. The cylindrical magnet 32 is made of, for example, a rare earth magnet material or a ferrite magnet material. In this embodiment, it is made of a neodymium rare earth magnet material. The cylindrical magnet 32 is magnetized for driving with 12 poles in the circumferential direction (tangential direction of a circle with the rotation axis R as the center and perpendicular to the rotation axis R). The cylindrical magnet 32 faces the nine salient poles of the laminated core 40 in the radial direction (that is, the direction orthogonal to the rotation axis R).

  The laminated core 40 has an annular portion and nine salient poles extending radially outward therefrom, and is fixed to the upper surface 4 d side of the base 4. The laminated core 40 is formed by, for example, laminating six thin electromagnetic steel plates having a thickness of 0.2 mm and integrating them by caulking. The laminated core 40 may be formed by, for example, laminating thin electromagnetic steel sheets having a thickness in the range of 0.1 mm to 0.8 mm, for example, in the range of 2 to 20 sheets. An insulating coating such as electrodeposition coating or powder coating is applied to the surface of the laminated core 40. A coil 42 is wound around each salient pole of the laminated core 40. When a three-phase substantially sinusoidal drive current flows through the coil 42, a drive magnetic flux is generated along the salient poles.

  The base 4 has an annular base protrusion 4e centered on the rotation axis R of the rotating body. The base protrusion 4e protrudes upward so as to surround the housing 102. The laminated core 40 is fixed to the base 4 by fitting the center hole 40a of the annular portion of the laminated core 40 to the outer peripheral surface 4g of the base protrusion 4e. In particular, the annular portion of the laminated core 40 is press-fitted into the base protruding portion 4e or bonded and fixed by clearance fitting. In the embodiment, in order to suppress the vibration of the laminated core 40, about 60% to 90% of the axial thickness dimension of the annular portion of the laminated core 40 is in pressure contact with the outer peripheral surface 4g of the base protruding portion 4e.

  A portion of the upper surface 4 d of the base 4 corresponding to the salient pole and the coil 42 is provided with an insulating sheet or tape 174 made of resin such as PET.

  The housing 102 includes a flat annular housing bottom portion 110, a cylindrical base-side surrounding portion 112 fixed to the outer peripheral side of the housing bottom portion 110, and an inner peripheral side of the housing bottom portion 110 that is fixed along the rotation axis R. Existing support protrusions 108. The housing 102 forms, together with the shaft 26, an annular support recess 166 into which the lower end of the shaft surrounding portion 28j enters.

  The base side surrounding portion 112 is surrounded by the base protrusion 4e. The base-side surrounding portion 112 is fitted in a bearing hole 4k that is a through-hole centered on the rotation axis R provided in the base 4, and is particularly fixed to the bearing hole 4k by bonding.

  The shaft 26 is formed with a support hole 26d that is a through-hole centered on the rotation axis R. The support protrusion 108 is inserted into the support hole 26d and fixed. In other words, the shaft 26 surrounds the support protrusion 108 and is fixed to the support protrusion 108.

  A shaft fixing screw hole 152 that is a non-penetrating screw hole is formed along the rotation axis R on the upper end surface 108 b of the support protrusion 108. The shaft fixing screw 6 enters the shaft fixing screw hole 152 and is screwed together. In order to improve the bonding strength, screwing and adhesion may be used in combination. Regarding the positional relationship among the shaft 26, the support protrusion 108, and the shaft fixing screw 6, the support protrusion 108 is sandwiched between the shaft 26 and the shaft fixing screw 6 in the radial direction, or the support protrusion 108 is the shaft 26 and the shaft fixing screw. 6 is interposed. The shaft fixing screw 6 does not contact the shaft 26 but is indirectly fixed to the shaft 26.

  The shaft 26 includes a body portion 26f that extends along the rotation axis R and surrounds the support protrusion 108, and a flange portion 26g that extends radially outward from the upper end portion of the body portion 26f.

  The ring portion 104 surrounds the flange portion 26g and is fixed to the outer peripheral surface 26h of the flange portion 26g. The ring portion 104 is fixed to the flange portion 26g by using both press fitting and adhesion. The adhesive between the ring portion 104 and the flange portion 26g also functions as a seal material that seals the gap between the ring portion 104 and the flange portion 26g to prevent the lubricant 92 from leaking out.

  The shaft surrounding portion 28j surrounds the body portion 26f. A lubricant 92 is interposed between the shaft surrounding portion 28j and the body portion 26f. That is, the inner peripheral surface 28k of the shaft surrounding portion 28j and the outer peripheral surface 26e of the body portion 26f are opposed to each other via the first gap 126, and the first gap 126 is filled with the lubricant 92. The lubricant 92 includes a phosphor. When the lubricant 92 is irradiated with light such as ultraviolet rays, the lubricant 92 emits, for example, blue or green light having a wavelength different from that of the irradiated light due to the action of the phosphor. When the lubricant 92 includes a phosphor, the liquid level of the lubricant 92 can be more easily inspected. Moreover, adhesion and leakage of the lubricant 92 can be easily detected.

  The shaft surrounding portion 28j is sandwiched between the flange portion 26g, the ring portion 104, and the housing 102 in the axial direction (that is, the direction parallel to the rotation axis R). A lubricant 92 is interposed in each of the shaft surrounding portion 28j and the ring portion 104, the shaft surrounding portion 28j and the flange portion 26g, and the shaft surrounding portion 28j and the housing 102. That is, the flange facing surface 28l of the shaft surrounding portion 28j and the lower surface 26i of the flange portion 26g face each other via the second gap 128, and the second gap 128 is filled with the lubricant 92. The flange facing surface 28l is a disk-shaped surface having a normal line substantially parallel to the rotation axis R. The lower surface 28m of the shaft surrounding portion 28j and the upper surface 110b of the housing bottom portion 110 are opposed to each other through the third gap 124, and the third gap 124 is filled with the lubricant 92.

  In the positional relationship between the base-side surrounding portion 112 and the shaft surrounding portion 28j, the base-side surrounding portion 112 surrounds the lower portion of the shaft surrounding portion 28j. Between the base side surrounding portion 112 and the shaft surrounding portion 28j, there is a fourth gap 132 between the inner peripheral surface 112a of the base side surrounding portion 112 and the outer peripheral surface 28n below the shaft surrounding portion 28j. A first taper seal 114 is formed, which is a portion that gradually widens upward. The first taper seal 114 has a first gas-liquid interface 116 of the lubricant 92, and suppresses leakage of the lubricant 92 by capillary action.

  An annular sleeve recess having the rotation axis R as the center is formed on the upper surface of the shaft surrounding portion 28j. The sleeve recess is recessed downward. The sleeve recess includes a first recess surface 154a extending obliquely downward in the radial direction from the outer periphery of the flange facing surface 28l, and a second recess surface extending substantially parallel to the radial direction from the outer periphery of the first recess surface 154a. 154b and a third recessed surface 154c extending axially upward from the outer peripheral edge of the second recessed surface 154b. The normal line of the first concave surface 154a is parallel to the direction intersecting the axial direction. In particular, the angle formed between the normal line of the first concave surface 154a and the rotation axis R may be in the range of 30 degrees to 60 degrees. The ring portion 104 enters the sleeve recess.

  The ninth gap 140 between the third recess surface 154c and the outer peripheral surface 104c of the ring portion 104 forms a second taper seal 118 that is a portion that gradually widens upward. The second taper seal 118 has a second gas-liquid interface 120 of the lubricant 92, and suppresses the leakage of the lubricant 92 by capillary action.

  The first gap 126 includes two radial dynamic pressure generating portions 156 and 158 that generate radial dynamic pressure in the lubricant 92 when the hub 28 rotates relative to the shaft 26. The two radial dynamic pressure generators 156 and 158 are axially separated from each other, and the first radial dynamic pressure generator 156 is positioned above the second radial dynamic pressure generator 158. A portion of the inner peripheral surface 28k of the shaft surrounding portion 28j corresponding to each of the two radial dynamic pressure generating portions 156, 158 has a herringbone-shaped or spiral-shaped first radial dynamic pressure generating groove 50, a second radial dynamic motion. A pressure generating groove 52 is formed. At least one of the first radial dynamic pressure generating groove 50 and the second radial dynamic pressure generating groove 52 is formed on the outer peripheral surface 26e of the body portion 26f instead of the inner peripheral surface 28k of the shaft surrounding portion 28j. Also good.

  The third gap 124 includes a first thrust dynamic pressure generating unit 160 that generates dynamic pressure in the axial direction in the lubricant 92 when the hub 28 rotates with respect to the shaft 26. A herringbone-shaped or spiral-shaped first thrust dynamic pressure generating groove 54 is formed in a portion of the lower surface 28 m of the shaft surrounding portion 28 j corresponding to the first thrust dynamic pressure generating portion 160. The first thrust dynamic pressure generating groove 54 may be formed on the upper surface 110b of the housing bottom portion 110 instead of the lower surface 28m of the shaft surrounding portion 28j.

  The second gap 128 includes a second thrust dynamic pressure generator 162 that generates axial dynamic pressure in the lubricant 92 when the hub 28 rotates relative to the shaft 26. A second thrust dynamic pressure generating groove 56 having a herringbone shape or a spiral shape is formed in a portion of the flange facing surface 28l of the shaft surrounding portion 28j corresponding to the second thrust dynamic pressure generating portion 162. The second thrust dynamic pressure generating groove 56 may be formed on the lower surface 26i of the flange portion 26g instead of the flange facing surface 28l of the shaft surrounding portion 28j.

  When the rotating body rotates relative to the fixed body, the first radial dynamic pressure generating groove 50, the second radial dynamic pressure generating groove 52, the first thrust dynamic pressure generating groove 54, and the second thrust dynamic pressure generating groove 56 are used. Each generate a dynamic pressure in the lubricant 92. With this dynamic pressure, the rotating body is supported in the radial direction and the axial direction without contacting the fixed body.

  The cover ring 12 is fixed by adhesion to, for example, the hub 28 of the rotating body so as to cover the second gas-liquid interface 120 existing in the ninth gap 140. The cover ring 12 may be fixed to, for example, the flange portion 26g of the fixed body instead of the rotating body. The cover ring 12 is formed in an annular shape from a metal material such as stainless steel or a resin material, for example. The cover ring 12 may include a porous body such as a sintered body or a charcoal filter so as to capture the gas or mist of the lubricant 92 scattered from the second gas-liquid interface 120.

  The shaft surrounding portion 28j includes a bypass communication hole 164 that bypasses the second thrust dynamic pressure generating portion 162, the first radial dynamic pressure generating portion 156, the second radial dynamic pressure generating portion 158, and the first thrust dynamic pressure generating portion 160. Is formed. The bypass communication hole 164 linearly penetrates the shaft surrounding portion 28j along the axial direction. A lubricant 92 is contained in the bypass communication hole 164, and the lubricant 92 flows through the bypass communication hole 164 particularly when there is an imbalance in dynamic pressure. As a result, the dynamic pressure is averaged. As a result, the levels of the first gas-liquid interface 116 and the second gas-liquid interface 120 can be kept appropriate even if there is an imbalance in the generated dynamic pressure, for example.

  A part of the edge of the upper end of the bypass communication hole 164 exists in the first concave surface 154a, and the remaining part exists in the flange facing surface 28l. An edge-facing surface that faces the first recess surface 154 a in the surface of the ring portion 104 has a shape corresponding to the upper edge of the bypass communication hole 164. In particular, on the edge-facing surface, an edge-corresponding recess 178 that surrounds the rotation axis R is formed at a position corresponding to the upper edge of the bypass communication hole 164. The edge-corresponding recess 178 is formed so as to cover a part of the upper edge of the bypass communication hole 164.

  FIGS. 3A and 3B are schematic diagrams for explaining the positional relationship between the edge corresponding recess 178 and the upper edge of the bypass communication hole 164. FIG. 3A is a bottom view of the ring portion 104. FIG. 3B is a top view of the shaft surrounding portion 28j. In FIG. 3B, the display of the second thrust dynamic pressure generating groove 56 is omitted for the sake of clarity.

  The outermost peripheral portion of a part 164 a of the upper edge of the bypass communication hole 164 existing on the first concave surface 154 a is inside the outermost peripheral portion of the edge corresponding concave portion 178. This positional relationship is indicated by broken lines in FIGS. 3 (a) and 3 (b). The remaining part 164b of the upper edge of the bypass communication hole 164 existing on the flange facing surface 28l is subjected to countersink processing, and the part 164b has a countersink surface 164c.

  The edge corresponding recess 178 is formed outside the flange facing surface 28l. Therefore, the counterbore surface 164c exists inside the edge corresponding recess 178. In other words, the edge-corresponding recess 178 is formed at a position away from the remaining part 164b of the edge.

  FIG. 4 is an enlarged view showing a part of FIG. 2 in an enlarged manner. The support protrusion 108 is fixed to the support hole 26d by using both press-fitting and adhesion. The shaft 26 surrounds the upper end portion 108 c of the support protruding portion 108 via the seventh gap 136. In the positional relationship between the flange portion 26g and the upper end portion 108c, the flange portion 26g surrounds the upper end portion 108c.

  The lower end portion 26j of the shaft 26 surrounds the support protrusion 108 via the eighth gap 138. An adhesive 184 is present in the seventh gap 136 and the eighth gap 138. The seventh gap 136 has a portion with a wide gap and a narrow portion, and the wide portion functions as an adhesive reservoir for accumulating the adhesive 184. The width of the narrow gap may be in the range of 20 μm to 30 μm. The eighth gap 138 is configured similarly to the seventh gap 136.

  The diameter D1 of the peripheral surface portion of the support hole 26d corresponding to the eighth gap 138 is larger than the diameter D2 of the outer peripheral surface 108a of the support protrusion 108 corresponding to the seventh gap 136. Therefore, at the initial stage of inserting the shaft 26 into the support protrusion 108, the shaft 26 is loosely fitted to the support protrusion 108.

  The support protrusion 108 is pressed against the shaft 26 between the seventh gap 136 and the eighth gap 138. In particular, between the seventh gap 136 and the eighth gap 138, there are two pressure contact portions 180, 182 in which the outer peripheral surface 108a of the support protrusion 108 is pressed into contact with the peripheral surface of the support hole 26d. The two pressure contact portions 180 and 182 are axially separated from each other, and the first pressure contact portion 180 is located above the second pressure contact portion 182. The press-fitting allowance in the first press-contact portion 180 and the second press-contact portion 182 may be about 5 μm. The second pressure contact portion 182 is located between the first radial dynamic pressure generating unit 156 and the second radial dynamic pressure generating unit 158 in the axial direction. In the positional relationship between the upper end portion 108 c and the radial dynamic pressure generating portion, the upper end portion 108 c exists above the upper end portion of the first radial dynamic pressure generating portion 156.

  Procedures for attaching the shaft 26 to the support protrusion 108 include: (1) Applying an adhesive 184 to either the peripheral surface of the support hole 26d or the outer peripheral surface 108a of the support protrusion 108, and then to the support hole 26d. Insert the support protrusion 108, or (2) apply the adhesive 184 to both the peripheral surface of the support hole 26d and the outer peripheral surface 108a of the support protrusion 108, and then insert the support protrusion 108 into the support hole 26d. There are two possible ways. According to the experiment by the present inventor, it was found that the bond strength obtained by the method (2) is significantly higher than the bond strength obtained by the method (1). In one example, the force required to pull the shaft 26 away from the support protrusion 108 was 60 kg in (2) and 50 kg in (1).

  The operation of the rotating device 100 configured as described above will be described. In order to rotate the magnetic recording disk 8, a three-phase drive current is supplied to the coil 42. When the drive current flows through the coil 42, magnetic flux is generated along the nine salient poles. Torque is applied to the cylindrical magnet 32 by this magnetic flux, and the rotating body and the magnetic recording disk 8 fitted thereto rotate. At the same time, the voice coil motor 16 swings the swing arm 14, so that the recording / reproducing head moves back and forth on the magnetic recording disk 8. The recording / reproducing head converts the magnetic data recorded on the magnetic recording disk 8 into an electric signal and transmits it to a control board (not shown), and the data sent from the control board in the form of an electric signal is recorded on the magnetic recording disk 8. Is written as magnetic data.

  According to the rotating device 100 according to the present embodiment, the shaft fixing screw 6 that fixes the top cover 2 to the shaft 26 is screwed into the shaft fixing screw hole 152 formed in the support protrusion 108. Therefore, in the configuration in which the shaft 26 is supported by the support protrusion 108, the length of engagement between the shaft fixing screw 6 and the shaft fixing screw hole 152 can be increased without increasing the thickness of the rotating device 100. Thereby, the coupling strength between the shaft fixing screw 6 and the support protrusion 108 can be increased, and the impact resistance and vibration resistance are improved.

  Further, in the rotating device 100 according to the present embodiment, the support protrusion 108 extends to the same height as the flange 26g in the axial direction. Further, the upper end portion 108 c of the support protruding portion 108 is positioned above the first radial dynamic pressure generating portion 156. Therefore, the part where the outer peripheral surface 108a of the support protrusion 108 and the peripheral surface of the support hole 26d face each other in the radial direction can be made longer. Thereby, the coupling strength between the shaft 26 and the support protrusion 108 can be increased.

  Further, in the rotating device 100 according to the present embodiment, the two pressure contact portions 180 and 182 have two gaps 136 at a portion where the outer peripheral surface 108a of the support protrusion 108 and the peripheral surface of the support hole 26d face each other in the radial direction. 138. Therefore, when the shaft 26 is inserted into the support protrusion 108, the insertion proceeds with a relatively small force at first, and press-fitting starts when the shaft 26 is inserted to a certain extent. Thereby, compared with the case where press-fitting occurs from the beginning, the shaft 26 can be easily coupled to the support protrusion 108 while maintaining the perpendicularity of the shaft 26. That is, the first loose-fitting state functions as a guide for press-fitting, and the press-fitting operation can be performed more easily while maintaining the squareness.

  Further, in the rotating device 100 according to the present embodiment, the shaft 26 is fixed to the support protrusion 108 by using both press-fitting and adhesion. Therefore, the bond strength can be further increased.

  In the rotating device 100 according to the present embodiment, the second press-contact portion 182 is located between the first radial dynamic pressure generator 156 and the second radial dynamic pressure generator 158 in the axial direction. Therefore, even if the shaft 26 expands due to the stress generated in the second pressure contact portion 182, the influence on the first radial dynamic pressure generating unit 156 and the second radial dynamic pressure generating unit 158 due to the expansion is reduced.

  The bypass communication hole 164 is usually formed by drilling the shaft surrounding portion 28j from above or below with a drill or a laser. Generally, after drilling, countersinking is often performed to remove edge burrs that may be present at the edge of the hole. This is to avoid the edge burrs from peeling off and entering the dynamic pressure generating portion and adversely affecting the generation of dynamic pressure.

  However, a part 164a of the upper end edge of the bypass communication hole 164 existing on the first recess surface 154a is countersunk because the first recess surface 154a is inclined with respect to the extending direction of the bypass communication hole 164. Processing is difficult or even if it can be done, it takes time. Therefore, in rotating device 100 according to the present embodiment, edge corresponding recess 178 is formed in ring portion 104. Therefore, even if an edge burr remains on a part 164a of the upper edge of the bypass communication hole 164 after the bypass communication hole 164 is formed, the possibility that the edge burr comes into contact with a member on the fixed body side and can be reduced can be reduced.

  In the rotating device 100 according to the present embodiment, the remaining portion 164b of the upper edge of the bypass communication hole 164 is subjected to countersink processing. Therefore, the possibility of peeling of edge burrs therefrom is reduced. Moreover, the edge corresponding | compatible recessed part 178 is formed in the position which remove | deviated from the remaining part 164b of the edge. Therefore, compared with the case where the edge-corresponding recess is large enough to cover the remaining portion 164b, the effect of the edge-corresponding recess 178 on the flow and dynamic pressure of the lubricant 92 is maintained while maintaining the effect of suppressing the peeling of the edge burr. Can be suppressed. As a result, the design of the rotating device 100 becomes easier.

  Moreover, according to the rotating device 100 according to the present embodiment, the second gas-liquid interface 120 of the lubricant 92 exists in the ninth gap 140. Therefore, the taper seal and the radial dynamic pressure generator are allowed to overlap in the axial direction. As a result, the axial distance between the first radial dynamic pressure generating portion 156 and the second radial dynamic pressure generating portion 158, that is, the bearing span, can be increased without being so limited by the length of the taper seal. The radial rigidity of the bearing can be increased.

  Conversely, the length of the taper seal can be increased without being constrained so much by the bearing span, so that a sufficient amount of the lubricant 92 can be held and scattering can be suppressed. Further, when the amount of the lubricant 92 to be held can be reduced, the ninth gap 140 and the fourth gap 132 can be narrowed accordingly, and the lubricant 92 when receiving an impact by increasing the capillary force, for example. Leakage can be reduced.

  The configuration and operation of the rotating device according to the embodiment have been described above. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective components, and such modifications are also within the scope of the present invention.

  In the embodiment, a so-called outer rotor type rotating device in which the cylindrical magnet 32 is located outside the laminated core 40 has been described, but the present invention is not limited thereto. For example, a so-called inner rotor type rotating device in which a cylindrical magnet is positioned inside a laminated core may be used.

  Although the case where a laminated core is used has been described in the embodiment, the core may not be a laminated core.

  In the embodiment, the case where the hub 28 is formed of a steel material has been described. However, the present invention is not limited to this. For example, in order to reduce the weight of the hub, the hub may be formed of a non-ferrous metal material such as an aluminum alloy or a resin material such as a liquid crystal polymer.

  In the embodiment, the case where the bearing hole 4k penetrates in the axial direction has been described. However, the present invention is not limited to this. For example, in order to improve the airtightness of the space in which the magnetic recording disk is stored, a bottom portion may be provided at the lower end of the bearing hole to close the lower end of the bearing hole. In order to further improve the airtightness, the bottom of the bearing hole may be formed seamlessly integrally with the base.

  In the embodiment, the case where the flange portion 26g surrounds the upper end portion 108c of the support projecting portion 108 has been described. However, the present invention is not limited to this. For example, the shaft fixing screw may be screwed into a screw hole provided in the shaft, and the distal end of the shaft fixing screw may enter and be fixed to the center hole formed in the support protrusion.

  FIG. 5 is a cross-sectional view showing the shaft 226 and its surroundings of the rotating device according to the first modification. A shaft fixing screw hole 252 is formed along the rotation axis R in the shaft 226. The shaft fixing screw hole 252 passes through the shaft 226. A support hole 226 d is formed along the rotation axis R in the lower end surface 226 c of the shaft 226. The shaft fixing screw hole 252 and the support hole 226d communicate with each other. The support protrusion 208 is inserted into the support hole 226d and fixed. In particular, the support protrusion 208 is fixed to the support hole 226d by using both press-fitting and adhesion. A non-through screw receiving hole 230 is formed along the rotation axis R on the upper end surface 208 a of the support protrusion 208.

  The shaft fixing screw 6 is screwed into the shaft fixing screw hole 252 and penetrates the shaft fixing screw hole 252. The lower end of the shaft fixing screw 6 enters the screw receiving hole 230 and is bonded and fixed there. That is, the adhesive 232 is interposed between the shaft fixing screw 6 and the support protrusion 208. The screw receiving hole may be a screw hole, and the shaft fixing screw 6 may be screwed into the screw receiving hole 230.

  FIG. 6 is an enlarged view of a portion surrounded by a broken line in FIG. The shaft 226 surrounds the base portion of the support protrusion 208 via the sixth gap 122. An adhesive 284 is present in the sixth gap 122. The sixth gap 122 has a wide part and a narrow part, and the wide part functions as an adhesive reservoir for storing the adhesive 284.

  The support protrusion 208 is pressed against the shaft 226 on the upper side of the sixth gap 122. In particular, on the upper side of the sixth gap 122, there is a pressure contact portion 280 where the outer peripheral surface 208b of the support protrusion 208 is pressed against the peripheral surface of the support hole 226d.

  A lower end surface 226 c of the shaft 226 is opposed to the upper surface of the housing bottom portion 210 in the axial direction through the fifth gap 134. When the shaft 226 is attached to the support protrusion 208, the height of the shaft 226 can be adjusted by the size of the fifth gap 134. Further, when the adhesive 284 is also present in the fifth gap 134, the fifth gap 134 functions as an adhesive reservoir and suppresses leakage of the adhesive 284.

  According to the rotating device according to the first modification, the shaft fixing screw 6 enters and is fixed to the screw receiving hole 230, so that the coupling strength between the shaft fixing screw 6 and the support protrusion 208 can be increased. Further, the length of engagement between the shaft fixing screw 6 and the shaft fixing screw hole 252 can be increased. Moreover, since the shaft fixing screw 6 and the shaft 226 are directly coupled, the coupling strength between them and the coupling strength between the top cover 2 and the shaft 226 can be increased.

  In this modification, the shaft fixing screw hole 252 corresponds to the shaft fixing screw 6, and the support hole 226 d of the shaft 226 corresponds to the support protrusion 208. Therefore, the support hole 226d has a larger diameter than the shaft fixing screw hole 252. As a result, the diameter of the pressure contact portion 280 between the support protrusion 208 and the shaft 226 can be increased. This contributes to an improvement in bond strength.

  FIG. 7 is a partial cross-sectional view illustrating a main part of a rotating device according to a second modification. FIG. 7 corresponds to FIG. The main difference between the first modification and the second modification is the shape of the outer peripheral surface 308b of the support protrusion 308.

FIG. 8 is a cross-sectional view showing a shaft 426 and its surroundings of a rotating device according to a third modification. The main difference between the first modification and the third modification is the length of the support protrusion 408. The support protrusion 408 according to the third modification is longer than the support protrusion 208 according to the first modification. In this case, the strength of adhesion between the shaft fixing screw 6 and the screw receiving hole 430 by the adhesive 432 can be increased.
Note that the shaft fixing screw 6 may be screwed into the screw receiving hole 430 using the screw receiving hole 430 as a screw hole instead of bonding with the adhesive 432.

  2 Top cover, 4 Base, 6 Shaft fixing screw, 8 Magnetic recording disk, 10 Data read / write section, 28 Hub, 40 Stacked core, 42 Coil, 92 Lubricant, 100 Rotating device, 156 First radial dynamic pressure generating section 158 Second radial dynamic pressure generator, R Rotating shaft.

Claims (7)

A rotating body on which the recording disk is to be placed;
A fixed body that rotatably supports the rotating body,
The fixed body is
An inner portion extending along the rotation axis of the rotating body;
An outer portion surrounding the inner portion and fixed to the inner portion;
A cover covering the rotating body;
A coupling portion for fixing the cover to the outer portion,
The rotating device according to claim 1, wherein the coupling portion enters a hole formed in the inner portion along a rotation axis.   The rotating device according to claim 1, wherein the coupling portion is coupled to the hole. The fixed body further includes a flange portion extending radially outward from an end portion of the outer side on the cover side,
The rotating device according to claim 1, wherein the flange portion surrounds an end portion of the inner side on the cover side. The dynamic pressure gap between the outer portion and the rotating body is a radial dynamic pressure generating portion that generates a radial dynamic pressure in the lubricant present in the dynamic pressure gap when the rotating body rotates with respect to the outer portion. Including
4. The rotating device according to claim 1, wherein an end portion on the cover side of the inner side portion is closer to the cover than an end portion on the cover side of the radial dynamic pressure generating portion. The outer portion surrounds the end portion on the cover side of the inner portion via a first gap,
5. The rotating device according to claim 1, wherein an end of the outer side opposite to the cover surrounds the inner side via a second gap.   The rotating device according to claim 5, wherein the inner portion is pressed against the outer portion between the first gap and the second gap. The dynamic pressure gap between the outer portion and the rotating body is a radial dynamic pressure generating portion that generates a radial dynamic pressure in the lubricant present in the dynamic pressure gap when the rotating body rotates with respect to the outer portion. Including
The radial dynamic pressure generating unit includes a first radial dynamic pressure generating unit and a second radial dynamic pressure generating unit that are spaced apart in the axial direction,
The portion where the inner portion is pressed against the outer portion is located between the first radial dynamic pressure generating portion and the second radial dynamic pressure generating portion in the axial direction. Rotating equipment.

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