JP2015046208A - Rotary apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary apparatus of a low cost.SOLUTION: A rotary apparatus 100 comprises a rotating body and a fixing body for supporting the rotating body rotatably. A lubricant 48 is interposed between the rotating body and the fixing body. The rotating body includes a spherical stored member 26 and a first thrust member 30. The fixing body includes a storage member 24 for storing the stored member 26 and a collar member 34 facing the first thrust member 30 in an axial direction. On at least one of a lower surface 30d of the first thrust member 30 and a top surface 34a of the collar member 34, a first thrust dynamic pressure generation groove 55 is formed. The first thrust dynamic pressure generation groove 55 makes the lubricant 48 generate fluid dynamic pressure when the rotating body rotates to the fixing body, and supports the rotating body in a state where the rotating body does not contact the fixing body.

Description

  The present invention relates to a rotating device that rotationally drives 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, tablet terminals, and portable music players is advancing.

  For example, Patent Document 1 proposes a motor that employs a fluid dynamic bearing mechanism as a bearing.

JP 2011-103150 A

  The disk drive device described in Patent Document 1 is required to be thinner. However, when the thickness is reduced, the shaft rigidity of the radial dynamic pressure bearing portion of the fluid dynamic pressure bearing is reduced, and the bearing rigidity may be reduced. When the bearing rigidity is lowered, the inclination of the rotating shaft of the rotating body when an unbalanced load is applied to the rotating body may increase, and in the worst case, the rotating body may contact the fixed body and cause a failure. For this reason, it is an issue to increase the bearing rigidity of the thrust dynamic pressure bearing portion by providing the thrust dynamic pressure bearing portion at a position relatively far from the rotation center so as to compensate for the decrease in rigidity of the radial dynamic pressure bearing portion due to the thinning. It is.

  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 rotary device that is advantageous in reducing the thickness by increasing the bearing rigidity of the thrust dynamic pressure bearing portion.

  In order to solve the above problems, a rotating device according to an aspect of the present invention includes a rotating body and a fixed body that rotatably supports the rotating body. A lubricant is interposed between the rotating body and the fixed body, and one of the fixed body and the rotating body is a three-dimensional shape obtained by rotating a plane figure having one side of the rotating shaft of the rotating body around the rotating shaft. A member to be stored, and a surrounding member having an annular end surface surrounding the member to be stored and extending radially outward. The member to be accommodated has an enclosed surface whose cross-sectional shape including the rotation axis of the rotating body is an elliptical arc shape including a circular arc or a tapered shape. The other of the fixed body and the rotating body includes a storage member that has a surrounding surface that surrounds the surrounding surface, and that stores a part of the storage member, and an opposing member that faces the surrounding member in the axial direction. Including. A thrust dynamic pressure generating groove is formed on at least one of the surface of the surrounding member facing the facing member or the surface of the facing member facing the surface. The thrust dynamic pressure generating groove is configured such that the rotating body rotates relative to the fixed body. In doing so, fluid dynamic pressure is generated in the lubricant, and the rotating body is supported in a non-contact state with respect to the fixed body.

  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, the bearing rigidity of a thrust dynamic pressure bearing part can be improved, and the rotary apparatus advantageous for thickness reduction can be provided.

FIG. 1A and FIG. 1B are a top view and a side view showing a rotating device according to the first embodiment. It is the sectional view on the AA line of Fig.1 (a). It is sectional drawing which shows the rotary equipment which concerns on 2nd Embodiment. 4A is a cross-sectional view taken along line BB in FIG. 3, FIG. 4B is a cross-sectional view taken along line CC in FIG. 3, and FIG. 4C is a cross-sectional view taken along line DD in FIG. . It is sectional drawing which shows the rotary equipment which concerns on 3rd Embodiment. It is sectional drawing which shows the rotary equipment which concerns on 4th Embodiment. It is sectional drawing which shows the rotary equipment which concerns on 5th Embodiment. It is sectional drawing which shows the rotary equipment which concerns on 6th Embodiment. It is sectional drawing which shows the rotary equipment which concerns on a modification.

  Hereinafter, the same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. 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, particularly a hard disk drive that mounts a magnetic recording disk and rotationally drives it.

(First embodiment)
Fig.1 (a) and FIG.1 (b) show the rotary apparatus 100 which concerns on 1st Embodiment. FIG. 1A is a top view of the rotating device 100. FIG. 1B is a side view of the rotating device 100. FIG. 1A shows a state in which the top cover 2 is removed in order to show the inner configuration of the rotating device 100. 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 top cover 2, and six screws 20. The rotating body includes a hub 28, a clamper 36, and a cap 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 magnetic recording disk 8 is mounted on the hub 28 and rotates as the hub 28 rotates.

  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 this case, one surface of the base 4 may be pushed up to form a convex portion, and the other surface may be provided with an embossed portion in which a concave portion is formed corresponding to the convex portion. Deformation of the base 4 can be suppressed by providing an embossed portion at a predetermined site. Further, the base 4 may be configured by combining a sheet metal part formed by pressing and a die cast part formed by molding by aluminum die casting.

  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 present 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 present embodiment, the coefficient of static friction on 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 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.

FIG. 2 is a cross-sectional view taken along line AA in FIG.
The rotating body includes a hub 28, a member to be stored 26, a member to be stored 90, a first thrust member 30, a second thrust member 31, a clamper 36, a cylindrical magnet 32, a cap 12, including. The fixed body includes a base 4, a storage member 24, a collar member 34, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46. The lubricant 48 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 or SUS303 having soft magnetism, and is formed in a predetermined shape having a substantially cup 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 hub protrusion 28 a that fits in the central hole 8 a of the magnetic recording disk 8, and a mounting portion 28 b that is provided radially outward from the hub protrusion 28 a. The magnetic recording disk 8 is placed on a disk placement surface 28c that is the upper surface of the placement portion 28b. The magnetic recording disk 8 is fixed to the hub 28 by being sandwiched between the clamper 36 and the mounting portion 28b.

  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 28c. The clamper 36 is engaged with the outer peripheral surface 28d of the hub protrusion 28a. The clamper 36 and the outer peripheral surface 28d of the hub protrusion 28a may be coupled by mechanical coupling means such as screwing, caulking, press-fitting, etc., 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 28a 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 protruding portion 28a are screwed together, a male screw is formed on the outer peripheral surface 28d of the hub protruding portion 28a, 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 28a, the clamper 36 may come into contact with the processing burr when the clamper 36 is screwed to the outer peripheral surface 28d, and the processing burr may be peeled off. . In order to remove such a processing burr beforehand, a burr removing process may be performed on the outer peripheral surface 28d of the hub protrusion 28a.

  A first thrust member 30 is provided on the lower surface of the hub protrusion 28a so as to surround the storage member 24. The first thrust member 30 has an annular shape and is made of a steel material such as SUS430 or SUS303 or a metal material such as a copper alloy. The first thrust member 30 is formed integrally with the hub 28. The first thrust member 30 and the hub 28 may be formed separately and combined.

  A receiving member holding portion 90 is provided on the inner peripheral surface 28g side of the hub protruding portion 28a. The stored member holding portion 90 has an annular shape and is formed of a steel material such as SUS430 or SUS303 or a metal material such as a copper alloy. The accommodated member holding portion 90 has a hole 90a provided coaxially with the rotation axis R of the rotating body. The stored member holding portion 90 is formed integrally with the hub 28. The accommodated member holding portion 90 and the hub 28 may be formed separately and combined.

  As an example, the member to be stored 26 is formed of a steel material such as SUJ2 or ceramic. The member to be stored 26 has a three-dimensional shape obtained by rotating a plane figure having one side of the rotation axis R of the rotating body around the rotation axis R. In the present embodiment, the member to be stored 26 has a three-dimensional shape obtained by rotating a semicircle having a diameter of the rotation axis R around the rotation axis R. That is, the member 26 to be stored has a spherical shape. Therefore, the side surface 26b of the member to be stored 26 has a spherical surface and is surrounded by the storage member 24 as described later. The accommodated member 26 is fixed to the accommodated member holding portion 90 by bonding or welding in a state where a part of the accommodated member 26 enters the hole 90a of the accommodated member holding portion 90. In particular, the stored member 26 is fixed to the stored member holding portion 90 so that the center C thereof is positioned on the rotation axis R. The stored member 26 may be held in a non-fixed state with the stored member holding portion 90.

  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 has twelve magnetic poles for driving 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 stator core 40 in the radial direction. The surface of the cylindrical magnet 32 is rust-proofed by electrodeposition coating or spray coating.

  The stator 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 stator core 40 is formed, for example, by stacking six thin electromagnetic steel plates having a thickness of 0.2 mm and integrating them by caulking. The stator core 40 may be formed by laminating thin electromagnetic steel sheets in the range of 0.1 mm to 0.8 mm, for example, in the range of 2 to 32 sheets. The surface of the stator core 40 is subjected to insulation coating by electrodeposition coating or powder coating. A coil 42 is wound around each salient pole of the stator 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 stator core 40 may be formed by solidifying magnetic powder such as a sintered body.

  The base 4 has an annular base protrusion 4e centered on the rotation axis R of the rotating body. The base protruding portion 4 e protrudes upward so as to surround the second thrust member 31. The stator core 40 is fixed to the base 4 by fitting the center hole 40a of the annular portion of the stator core 40 to the outer peripheral surface 4f of the base protrusion 4e. In particular, the annular portion of the stator core 40 is press-fitted into the base protruding portion 4e or bonded and fixed by a clearance fit.

  A portion of the upper surface 4d of the base 4 corresponding to the salient pole and the coil 42 is provided with an insulating sheet or insulating tape 44 made of resin such as PET. A suction plate 46 made of a magnetic material such as iron is provided in a portion of the upper surface 4d of the base 4 that faces the cylindrical magnet 32 in the axial direction (direction parallel to the rotation axis R). The suction plate 46 is fixed to the base 4 by caulking or bonding. Since the suction plate 46 is attracted to the cylindrical magnet 32 by magnetic force, a downward force in the axial direction is applied to the cylindrical magnet 32, and this force is a force that suppresses the lifting of the rotating body during the rotation of the rotating body.

  The base 4 is provided with a non-through hole 4g centered on the rotation axis R of the rotating body. The hole 4g may be a through hole. The storage member 24 is inserted into the hole 4g and fixed. The storage member 24 rotatably supports the member to be stored 26 via the lubricant 48. As a result, the rotating body is rotatably supported with respect to the base 4.

  The storage member 24 has a bottomed cup shape in which a hollow body portion 24a and a bottom portion 24b are integrally formed, and is bonded and fixed to the base 4 with the bottom portion 24b facing downward, for example. The hollow body portion 24a has a cylindrical inner peripheral surface 24c. The stored member 26 is accommodated in the storage member 24, and the inner peripheral surface 24 c surrounds the side surface 26 b of the stored member 26 through the radial gap 53.

  A second thrust member 31 is provided so as to surround the storage member 24. The second thrust member 31 has a cylindrical portion 31a and a flange portion 31b extending radially inward from the lower end thereof, and the second thrust member 31 has an L-shaped cross section. The second thrust member 31 surrounds the first thrust member 30 and is fixed to the outer peripheral surface 30 c of the first thrust member 30. The second thrust member 31 is fixed to the first thrust member 30 by using both press fitting and adhesion. The adhesive between the second thrust member 31 and the first thrust member 30 also functions as a sealing material that seals the gap between the second thrust member 31 and the first thrust member 30 and prevents the lubricant 48 from leaking out. To do.

  The collar member 34 has an annular shape and is provided on the outer peripheral surface 24 d side of the storage member 24. The collar member 34 is formed integrally with the storage member 24. The collar member 34 may be formed separately from the storage member 24. In this case, the collar member 34 may be formed of a material different from that of the storage member 24. The lower surface 30d of the first thrust member 30, the inner peripheral surface 31c of the cylindrical portion 31a, and the upper surface 31d of the flange portion 31b form an annular recess 60 that is recessed outward in the radial direction. The collar member 34 is accommodated in the annular recess 60. The upper surface 34 a of the collar member 34 and the lower surface 30 d of the first thrust member 30 are opposed to each other in the axial direction via an annular first thrust gap 57. Further, the lower surface 34 b of the collar member 34 and the upper surface 31 d of the flange portion 31 b are opposed to each other in the axial direction via the annular second thrust gap 58.

  Between the flange portion 31b of the second thrust member 31 and the storage member 24, there is a gap 72 between the inner peripheral surface 31e of the flange portion 31b and the outer peripheral surface 24d of the storage member 24, that is, air on the outlet side, etc. A taper seal 70 is formed which gradually spreads toward the space where the gas exists. If it demonstrates from another viewpoint, the clearance gap between the taper seals 70 will be gradually widened toward the exit side from the back side in which the lubricant 48 exists. In particular, both the inner peripheral surface 31e of the flange portion 31b and the outer peripheral surface 24d of the storage member 24 are formed so as to have a smaller diameter, and the reduction ratio of the inner peripheral surface 31e of the flange portion 31b is the ratio of the storage member 24. The taper shape of the taper seal 70 is realized by being smaller than the ratio of the diameter reduction of the outer peripheral surface 24d. Further, the taper seal 70 is formed in a position farther from the rotation axis R in the rear side region than in the outlet side region. During rotation of the rotating body, a radially outward force due to centrifugal force acts on the lubricant 48 in the taper seal 70. Since the taper seal 70 is located on the outer side in the radial direction from the region on the outlet side, the force acts to push the lubricant 48 into the inner side. Further, the taper seal 70 has a gas-liquid interface 86 of the lubricant 48 and functions as a capillary seal that suppresses leakage of the lubricant 48 by capillary force.

  The cap 12 is formed in a substantially disc shape from a metal material such as stainless steel or a resin material. The cap 12 is fixed to the upper surface 90b of the stored member holding portion 90 by, for example, adhesion so as to close the upper end of the hole 90a of the stored member holding portion 90.

  The lubricant 48 is continuously interposed in a region on the back side from the gas-liquid interface 86 in the gap between the rotating body and the fixed body. In particular, a lubricant 48 is provided in the gap between the member 26, the first thrust member 30, and the second thrust member 31 that are part of the rotating body, and the housing member 24 and the collar member 34 that are part of the fixed body. Is filled. The lubricant 48 includes a phosphor. When the lubricant 48 is irradiated with light such as ultraviolet rays, the lubricant 48 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 48 contains a phosphor, the liquid level of the lubricant 48 can be more easily inspected. Further, the adhesion and leakage of the lubricant 48 can be easily detected.

  The upper surface 34 a of the collar member 34 has a first thrust dynamic pressure groove forming region 63. A spiral or herringbone-shaped first thrust dynamic pressure generating groove 55 is formed in the first thrust dynamic pressure groove forming region 63. The first thrust dynamic pressure generating groove 55 is formed on the lower surface 30d of the first thrust member 30 instead of the first thrust dynamic pressure groove forming area 63 or in addition to the first thrust dynamic pressure groove forming area 63. Also good.

  The lower surface 34 b of the collar member 34 has a second thrust dynamic pressure groove forming region 64. In the second thrust dynamic pressure groove forming region 64, a second thrust dynamic pressure generating groove 56 having a spiral shape or a herringbone shape is formed. The second thrust dynamic pressure generating groove 56 is formed on the upper surface 31d of the flange portion 31b of the second thrust member 31 instead of the second thrust dynamic pressure groove forming area 64 or in addition to the second thrust dynamic pressure groove forming area 64. May be formed. Further, a configuration without the second thrust dynamic pressure groove forming region 64, that is, a configuration without the second thrust dynamic pressure generating groove 56 is also possible.

  The first thrust dynamic pressure generating groove 55 and the second thrust dynamic pressure generating groove 56 generate fluid dynamic pressure in the lubricant 48 when the rotating body rotates with respect to the fixed body. In particular, the first thrust dynamic pressure generating groove 55 and the second thrust dynamic pressure generating groove 56 generate fluid dynamic pressure in the pump-in direction in which the generated dynamic pressure pushes the lubricant 48 toward the rotation axis R side. The dynamic pressure in the pump-in direction is such that the first thrust gap 30 between the first thrust member 30 and the collar member 34, the second thrust gap 58 between the second thrust member 31 and the collar member 34, the housed member 26 and the housed member 24. The levitation force in the direction away from each other acts on the gap.

  The inner peripheral surface 24 c of the hollow body 24 a has a radial dynamic pressure groove forming region 62. In the radial dynamic pressure groove forming region 62, a spiral dynamic or herringbone-shaped radial dynamic pressure generating groove 50 is formed. The radial dynamic pressure generating groove 50 generates a fluid dynamic pressure in the radial direction in the lubricant 48 when the rotating body rotates with respect to the fixed body. The radial fluid dynamic pressure acts so that the radial gap 53 between the storage member 24 and the member to be stored 26 is substantially constant. That is, the member to be stored 26 is centered by the fluid dynamic pressure in the radial direction so that the center C thereof is positioned on the central axis of the cylindrical inner peripheral surface 24c. The radial dynamic pressure generating groove 50 may be formed in the receiving member 26 instead of the radial dynamic pressure groove forming area 62 or in addition to the radial dynamic pressure groove forming area 62.

  The first thrust dynamic pressure groove forming region 63 is a belt-like region surrounding the rotation axis R, and is formed so as to be substantially orthogonal to the axial direction. That is, the first thrust dynamic pressure groove forming region 63 is a disc-shaped region with the rotation axis R as the center. The first thrust dynamic pressure groove forming region 63 is formed such that the radial difference between the inscribed circle and the circumscribed circle is larger than the axial dimension of the radial dynamic pressure groove forming region 62. By forming in this way, the fluid dynamic pressure generated by the first thrust dynamic pressure generating groove 55 is increased as compared with the case where it is not, and the bearing rigidity of the thrust dynamic pressure bearing portion is increased. When the bearing rigidity of the thrust dynamic pressure bearing portion is increased, for example, even when an eccentric load is applied to the rotating body and a moment force is applied to the rotating shaft R of the rotating body, the inclination of the rotating shaft R can be suppressed. Even when the rotating device is thinned, the first thrust dynamic pressure groove forming region 63 does not become small, so that it is possible to prevent a decrease in fluid dynamic pressure and bearing rigidity generated by the first thrust dynamic pressure generating groove 55. The same applies to the second thrust dynamic pressure groove forming region 64.

  The rotating body and the fixed body are configured such that the center of gravity G of the rotating body when the magnetic recording disk 8 is placed on the hub 28 is located at the center C of the member 26 to be stored.

  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 hub 28 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 member to be stored 26 is formed in a spherical shape. According to the inventor's experience as a person skilled in the art, for example, a spherical member made of a steel material can relatively easily obtain a high shape accuracy. Therefore, according to the rotating device 100 using the spherical member 26, a reduction in the rotation accuracy can be suppressed even when the rotating device 100 is thinned. Further, the cost of the rotating device 100 can be reduced.

  Further, according to the rotating device 100 according to the present embodiment, the fluid dynamic pressure generated by the first thrust dynamic pressure generating groove 55 is relatively large. Therefore, the radial dynamic pressure generating groove 50 only needs to perform the function of centering. Therefore, the radial dynamic pressure groove forming region 62 may be one and the axial dimension thereof may be relatively small. As a result, the axial dimension of the rotating device 100 can be made relatively small. For example, the axial dimension of the rotating device 100 can be set to 4.1 mm or less.

(Second Embodiment)
The main difference between the rotating device 100 according to the first embodiment and the rotating device according to the second embodiment is the shape of the storage member.
FIG. 3 is a cross-sectional view of the rotating device 200 according to the second embodiment. FIG. 3 corresponds to FIG. The rotating body includes a hub 28, a member to be stored 26, a member to be stored 90, a first thrust member 30, a second thrust member 31, a clamper 36, a cylindrical magnet 32, a cap 12, including. The fixed body includes a base 4, a storage member 124, a collar member 34, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46.

  The storage member 124 has a bottomed cup shape in which a hollow body portion 124a and a bottom portion 24b are integrally formed. The hollow body portion 124a has a cylindrical inner peripheral surface 124c. In particular, the inner peripheral surface 124c has a cylindrical shape whose central axis is inclined with respect to the rotation axis R by an angle θ. The storage member 26 is accommodated in the storage member 124, and the inner peripheral surface 124 c surrounds the side surface 26 b through the radial gap 53. When the rotating body is not rotating, the inner peripheral surface 124c and the side surface 526b of the member to be stored 526 are at least partially in contact with each other.

  4A is a cross-sectional view taken along line BB in FIG. 3, FIG. 4B is a cross-sectional view taken along line CC in FIG. 3, and FIG. 4C is a cross-sectional view taken along line DD in FIG. . As is apparent from FIGS. 4A to 4C, the member 26 to be stored is different from the inner peripheral surface 124c of the storage member 124 on the surface in FIG. 4A and the surface in FIG. It is eccentric to the opposite side. As a result, the dynamic pressure relatively increases in the narrow gap portions, so that the combined dynamic pressure in the cross section taken along the line BB and the cross section taken along the line DD occurs at a position indicated by P. That is, the combined dynamic pressure P in the opposite direction is generated on the surface of FIG. 4A and the surface of FIG. 4C. This dynamic pressure P increases as the gap decreases, and decreases as the gap increases. Accordingly, since the two dynamic pressures P are balanced in a substantially equal gap state, the self-alignment mechanism acts so that the gap 153 between the storage member 124 and the member 26 to be stored is substantially constant. That is, the member to be stored 26 is centered by the fluid dynamic pressure in the radial direction so that its center C is located on the central axis of the cylindrical inner peripheral surface 124c.

  Since the BB line section and the DD line section are displaced in the axial direction, the dynamic pressure P in the BB line section has a downward component force, and the dynamic pressure P in the DD line section is upward. Have a component power of. The upward component force and the downward component force act on the member to be stored 26 so as to suppress axial position fluctuations. As a result, since the member to be stored 26 is supported by the dynamic pressure P in the radial direction and the axial direction, it is possible to maintain a more stable rotation.

  According to the rotating device 200 according to the present embodiment, the same operational effects as the operational effects exhibited by the rotating device 100 according to the first embodiment are exhibited.

(Third embodiment)
The main difference between the rotating device 100 according to the first embodiment and the rotating device according to the third embodiment is the shapes of the base and the second thrust member.
FIG. 5 shows a cross-sectional view of a rotating device 300 according to the third embodiment. FIG. 5 corresponds to FIG. The rotating body includes a hub 28, a member to be stored 26, a member to be stored 90, a first thrust member 30, a second thrust member 231, a clamper 36, a cylindrical magnet 32, a cap 12, including. The fixed body includes a base 204, a storage member 24, a collar member 34, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46.

  The second thrust member 231 has a cylindrical portion 31a and a flange portion 231b extending radially inward from the lower end thereof. Unlike the flange portion 31b of the first embodiment, the flange portion 231b is formed with an annular thrust concave portion 231f that is recessed upward from the outer edge of the lower end in the direction of the rotation axis R.

  The base 204 is provided with a through hole 204g centering on the rotation axis R of the rotating body. The storage member 24 is inserted into the through hole 204g and fixed. Further, the base 204 has an entry portion 204h that enters the thrust recess 231f.

  A gap 88 between the second thrust member 31 and the base 204 communicates with the motor internal space 84 sandwiched between the hub 28 and the base 4 and the gas side of the gas-liquid interface 86. That is, the gap 88 communicates the gas-liquid interface 86 and the motor internal space 84. As described above, the flange portion 231b has the thrust concave portion 231f, and the base 204 has the entry portion 204h that enters the thrust concave portion 231f, whereby the gap 88 is narrowed and the distance is lengthened. The gap 88 is provided with a plurality of bent portions. Thereby, the passage resistance of the gap 88 can be increased.

  According to the rotating device 300 according to the present embodiment, the same effects as the effects achieved by the rotating device 100 according to the first embodiment are exhibited. In addition, according to the rotating device 300 according to the present embodiment, the gap 88 between the second thrust member 31 and the base 204 is narrowed and the distance is lengthened. The gap 88 is provided with a plurality of bent portions. Thereby, the passage resistance of the gap 88 can be increased. Therefore, the gap 88 functions as a labyrinth for the lubricant 48 that evaporates from the gas-liquid interface 86 of the taper seal 70 and reduces the evaporation amount of the lubricant 48.

(Fourth embodiment)
The main difference between the rotating device 100 according to the first embodiment and the rotating device according to the fourth embodiment is the shapes of the member to be stored and the storing member.
FIG. 6 shows a cross-sectional view of a rotating device 400 according to the fourth embodiment. FIG. 6 corresponds to FIG. The rotating body includes a hub 28, a member to be stored 326, a member to be stored 390, a first thrust member 330, a second thrust member 31, a clamper 36, and a cylindrical magnet 32. The fixed body includes a base 4, a storage member 24, a collar member 34, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46.

  A receiving member holding portion 390 is provided on the inner peripheral surface side 28g side of the hub protruding portion 28a. Unlike the stored member holding portion 90 of the first embodiment, the stored member holding portion 390 has a disk shape.

  The member 326 to be stored is formed of a steel material such as SUS430 or SUS303, or a metal material such as a copper alloy. The member to be stored 326 has a truncated cone shape, and is fixed to the member to be stored holding portion 390 so that the center axis thereof coincides with the rotation axis R. Therefore, the side surface 326b of the member to be stored 326 has a truncated cone shape. The member to be stored 326 may be formed integrally with the first thrust member 30.

  The storage member 324 has a bottomed cup shape in which a hollow body portion 324a and a bottom portion 324b are integrally formed, and is bonded and fixed to the base 4 with the bottom portion 324b facing down, for example. The hollow body 324a has a truncated cone-shaped inner peripheral surface 324c. The storage member 326 is accommodated in the storage member 324, and the inner peripheral surface 324 c surrounds the side surface 326 b of the storage member 326 via the radial gap 353.

  According to the rotating device 400 according to the present embodiment, the same operational effects as the operational effects exhibited by the rotating device 100 according to the first embodiment are exhibited.

(Fifth embodiment)
In the first to fourth embodiments, the case where the member to be stored is fixed to the rotating body has been described. In the fifth embodiment, the case where the member to be stored is fixed to the fixed body will be described.

  FIG. 7 shows a cross-sectional view of a rotating device 500 according to the fifth embodiment. FIG. 7 corresponds to FIG. The rotating body includes a hub 28, a storage member 424, a first thrust member 30, a second thrust member 231, a clamper 36, a cylindrical magnet 32, and a cap 12. The fixed body includes a base 204, a stored member holding portion 490, a collar member 34, a stored member 426, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46.

  The stored member holding portion 490 has a substantially cylindrical shape, and is formed of a steel material such as SUS430 or SUS303 or a metal material such as a copper alloy. The stored member holding portion 490 is inserted into the through hole 204g of the base 204 and fixed. A holding recess 490 b is formed on the upper surface 490 a of the stored member holding portion 490. The collar member 34 is fixed to the receiving member holding portion 490. In particular, the collar member 34 is fixed to the storage member holding portion 490 so as to surround the storage member 424.

  The member to be stored 426 is made of a steel material such as SUJ2 or ceramic. The member to be stored 426 has a spherical shape, and is fixed to the member to be stored holding part 490 by bonding or welding in a state where a part thereof enters the holding recess 490b. In particular, the member to be stored 426 is fixed to the member to be stored holding portion 490 so that its center C is located on the rotation axis R.

  A storage member 424 is coupled to the peripheral surface of the hole 30 b of the first thrust member 30. The storage member 424 has a cylindrical shape and is made of a steel material such as SUS430 or SUS303 or a metal material such as a copper alloy. The storage member 426 is accommodated in the storage member 424. The inner peripheral surface 424 c of the storage member 424 has a cylindrical shape, and surrounds the side surface 426 b of the storage target member 426 via the radial gap 453. The storage member 424 may be formed integrally with the first thrust member 30.

  A gap 472 between the inner peripheral surface 31e of the flange portion 231b and the outer peripheral surface 490c of the stored member holding portion 490 is disposed between the flange portion 231b of the second thrust member 31 and the stored member holding portion 490. A taper seal 470 that gradually widens is formed. The taper seal 470 corresponds to the taper seal 70 of the third embodiment.

  The cap 12 is fixed to the upper surface 424a of the storage member 424 by adhesion, for example, so as to close the upper side of the storage member 424.

  A gap between the storage member 424, the first thrust member 30, the cap 412, and the second thrust member 231 that are a part of the rotating body, and the storage member 426 and the storage member holder 490 that are a part of the fixed body. Is filled with a lubricant 48.

  The inner peripheral surface 424 c of the storage member 424 has a radial dynamic pressure groove forming region 462. In the radial dynamic pressure groove forming region 462, a radial dynamic pressure generating groove 450 having a spiral shape or a herringbone shape is formed. The radial dynamic pressure groove forming region 462 and the radial dynamic pressure generating groove 450 correspond to the radial dynamic pressure groove forming region 62 and the radial dynamic pressure generating groove 50 of the third embodiment, respectively.

  According to the rotating device 500 according to the present embodiment, the same operational effects as the operational effects exhibited by the rotating device 300 according to the third embodiment are exhibited.

(Sixth embodiment)
The main difference between the rotating device 100 according to the fifth embodiment and the rotating device according to the sixth embodiment is the shapes of the member to be stored and the storing member.
FIG. 8 is a cross-sectional view of a rotating device 600 according to the sixth embodiment. FIG. 8 corresponds to FIG. The rotating body includes a hub 28, a storage member 524, a first thrust member 30, a second thrust member 231, a clamper 36, a cylindrical magnet 32, and a cap 12. The fixed body includes a base 204, a stored member holding portion 490, a collar member 34, a stored member 526, a stator core 40, a coil 42, an insulating tape 44, and a suction plate 46.

  The member to be stored 526 is made of a steel material such as SUS430 or SUS303 or a metal material such as a copper alloy. The member 526 to be stored has a truncated cone shape, and is fixed to the first thrust member 530 so that the central axis thereof coincides with the rotation axis R. Therefore, the side surface 526b of the member to be stored 526 has a truncated cone shape. Note that the member to be stored 526 may be formed integrally with the member to be stored 490.

  The storage member 524 has a cylindrical shape. The storage member 526 is accommodated in the storage member 524, and the inner peripheral surface 524 c surrounds the side surface 526 b of the storage member 526 through the radial gap 553. The inner peripheral surface 524c includes a tapered surface having a smaller diameter toward the lower side. When the rotating body is not rotated, the inner peripheral surface 524c and the side surface 526b of the member to be stored 526 are at least partially in contact with each other.

  According to the rotating device 600 according to the present embodiment, the same operational effects as the operational effects exhibited by the rotating device 500 according to the fifth embodiment are exhibited.

  The configuration and operation of the rotating device according to the embodiment have been described above. It is to be understood by those skilled in the art that these embodiments are exemplifications, and various modifications can be made to the combination of each component, and such modifications are also within the scope of the present invention.

  In the first to fifth embodiments, the case where the number of salient poles of the stator core 40 is nine has been described, but the present invention is not limited to this. The number of salient poles of the stator core 40 may be an integer multiple of 3 from 6 to 36, for example. These descriptions are merely examples, and the number of salient poles is not limited to these ranges.

  In the first to fifth embodiments, the case where the cylindrical magnet 32 is magnetized for driving with 12 poles has been described. However, the present invention is not limited to this. The cylindrical magnet 32 may be magnetized for driving with an even number of poles, for example, 8 to 16. These descriptions are merely examples, and the number of driving magnetic poles is not limited to these ranges.

  Although the case where the inner peripheral surface 424c of the storage member 424 is cylindrical has been described in the fifth embodiment, the present invention is not limited to this. The inner peripheral surface 424c can have various shapes. FIG. 9 is a cross-sectional view showing a rotating device 700 according to a modification. FIG. 9 corresponds to FIG. In this modification, the inner peripheral surface 424c includes a tapered surface having a smaller diameter toward the lower side. When the rotating body is not rotated, the inner peripheral surface 424c and the side surface 426b of the member to be stored 426 are in contact with each other.

  4 base, 8 magnetic recording disk, 10 data read / write section, 12 cap, 24 storage member, 26 member to be stored, 28 hub, 30 first thrust member, 31 second thrust member, 32 cylindrical magnet, 40 stator core, 42 coils, 48 lubricants, 100 rotating equipment.

Claims (11)

A rotating body,
A fixed body that rotatably supports the rotating body,
A lubricant is interposed between the rotating body and the fixed body,
One of the fixed body and the rotating body surrounds the receiving member, and a three-dimensional receiving member obtained by rotating a plane figure having one side of the rotating shaft of the rotating member around the rotating shaft. And an encircling member having an annular end surface extending radially outwardly,
The member to be stored has an enclosed surface that has an elliptical arc shape or a tapered shape including a circular arc as a cross-sectional shape including a rotation axis of the rotating body,
The other of the fixed body and the rotating body has an encircling surface that encircles the encircling surface, a housing member that houses a part of the housing member, and is opposed to the surrounding member in the axial direction An opposing member,
A thrust dynamic pressure generating groove is formed on at least one of the surface of the surrounding member facing the facing member or the surface of the facing member facing the surface,
The thrust dynamic pressure generating groove generates fluid dynamic pressure in the lubricant when the rotating body rotates with respect to the fixed body, and supports the rotating body in a non-contact state with respect to the fixed body. Rotating equipment characterized by   The rotating device according to claim 1, wherein the member to be stored includes a sphere having a center on a rotation axis of the rotating body, and the surrounding surface is a spherical surface of the sphere. The rotating body is configured to be able to mount a recording disk,
The rotating body and the fixed body are configured such that the center of gravity of the rotating body when a recording disk is mounted on the rotating body is positioned at substantially the center in the axial direction of the member to be stored. The rotating device according to claim 1 or 2.   4. The storage member according to claim 1, further comprising a radial dynamic pressure generating groove that generates fluid dynamic pressure in the lubricant when the rotating body rotates with respect to the fixed body. Rotating equipment as described.   5. The rotating device according to claim 4, wherein a radial difference between an inscribed circle and a circumscribed circle in the thrust dynamic pressure generating groove forming region is larger than an axial distance of the radial dynamic pressure generating groove forming region.   6. The rotating device according to claim 1, wherein the surrounding surface includes a tapered surface with which the surrounding surface is in contact when the rotating body is not rotated.   A portion of the surrounding surface that is in contact with the surrounding surface when the rotating body is not rotating has an annular shape, and a center axis thereof is inclined at a predetermined angle with respect to the rotating shaft of the rotating body. The rotating device according to any one of claims 1 to 5.   The rotating device according to claim 1, wherein the facing member is formed integrally with the storage member. A further surrounding member that is fixedly supported by the surrounding member and faces the opposing member in the axial direction;
2. The thrust dynamic pressure generating groove is formed in at least one of the surface of the other surrounding member facing the facing member or the surface of the facing member facing the surface. The rotating device according to any one of 8.   The rotating device according to any one of claims 1 to 9, wherein the gap between the rotating body and the fixed body includes a taper seal in which a gas-liquid interface of the lubricant exists.   The rotating body and the fixed body are configured such that the size of the rotating device in the rotation axis direction of the rotating body is 4.1 mm or less. Rotating equipment.

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