JP2012163203A - Rotating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rigidity of a bearing, or prevent leakage of a lubricant.SOLUTION: A rotating device 100 includes a fixed body having a base 4 and a shaft 26, a hub 28, and a rotating body having a rotating-body-side encircling member 105 fixed to the hub 28 and encircling the shaft 26. A lubricant 92 is interposed between the fixed body and the rotating body. The rotating-body-side encircling member 105 and the shaft 26 are each formed with a radial dynamic pressure generating groove. The fixed body includes a base-side encircling member 102 having a disk part encircling the base-side portion of the shaft 26 and a cylinder part encircling the rotating-body-side encircling member. The base-side encircling member 102 has the disk part fixed to the shaft 26 by interference fitting, and has the cylinder part fixed to the base 4. An air-liquid interface is located in a gap in the radial direction between the inner periphery of the cylinder part and the outer periphery of the rotating-body-side encircling member 105.

Description

  The present invention relates to a rotating device in which a shaft is fixed to a fixed body side.

  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 to portable electronic devices such as notebook computers is advancing. For disk drive devices mounted on such portable electronic devices, compared to devices mounted on stationary electronic devices such as desktop PCs (Personal Computers), impacts such as dropping and vibrations caused by carrying. Therefore, it is required to improve impact resistance and vibration resistance so that it can withstand the above.

  For example, Patent Document 1 proposes a motor in which a shaft is fixed to a base plate and a fluid dynamic pressure bearing mechanism is used as a bearing.

JP 2010-127448 A

  In a conventional shaft-fixed motor as described in Patent Document 1, a dynamic pressure generating portion is formed so as to be sandwiched between two tapered seal portions in the direction of the rotation axis R. In this configuration, when the thickness of the motor is defined, the dimension of the dynamic pressure generating portion in the direction of the rotation axis R must be reduced. This causes a decrease in the rigidity of the bearing, which can adversely affect the shock resistance and vibration resistance of the motor.

  Alternatively, the dimension of the taper seal in the direction of the rotation axis R must be reduced. At this time, in order to maintain the lubricant holding amount of the taper seal, the capillary force is reduced by widening the gap in the radial direction. When the capillary force of the taper seal becomes small, there is a concern about leakage of the lubricant.

  Such a problem may occur not only in the motor but also in other types of rotating equipment, particularly rotating equipment in which the shaft is fixed to the stationary body and a fluid dynamic pressure bearing is employed.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a rotating device that can improve the rigidity of the bearing or reduce the leakage of the lubricant.

  One embodiment of the present invention relates to a rotating device. The rotating device includes a fixed body having a base and a shaft fixed to the base, a hub on which a recording disk is to be placed, and a hub hole provided in the hub so as to surround the shaft. A rotating body having a rotating body side surrounding member. A lubricant is continuously interposed between the fixed body and the rotating body, and the lubricant has at least a first gas-liquid interface and a second gas-liquid interface. A radial dynamic pressure generating groove for generating a radial dynamic pressure is formed on one of the surfaces of the rotating body side surrounding member and the shaft in contact with the lubricant. The fixed body includes a base-side surrounding member having a disk portion surrounding the base side of the shaft and a cylindrical portion surrounding the rotating body-side surrounding member. In the base-side surrounding member, the disk portion is fixed to the base side of the shaft by an interference fit, and the cylindrical portion is bonded and fixed to a through hole provided in the base. The first gas-liquid interface is located in a radial gap between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the rotating body-side surrounding member.

  According to this aspect, since the radial dynamic pressure generating groove and the first gas-liquid interface are provided overlapping in the axial direction, the dimension of the radial dynamic pressure generating groove in the axial direction can be increased.

  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.

  According to the present invention, the rigidity of the bearing can be improved.

FIG. 1 is a diagram illustrating a rotating device according to an embodiment. It is the sectional view on the AA line of FIG. FIG. 3 is an enlarged cross-sectional view showing the periphery of a lubricant path in FIG. 2 in an enlarged manner. It is an expanded sectional view which expands and shows the circumference of the course of the lubricant of a modification. It is an expanded sectional view which shows the base side member in which the shaft was formed integrally with the base side surrounding member.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components and members 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 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 is a diagram illustrating a rotating device 100 according to an embodiment. FIG. 1 is a top view of the rotating device 100 with a top cover (not shown) 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 and a shaft 26 fixed to the base 4. The rotating body includes a hub 28.
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 two magnetic recording disks 8.
The base 4 is formed by molding an aluminum alloy by die casting. The base 4 includes a bottom plate portion 4a that forms the bottom portion of the rotating device 100, and an outer peripheral wall portion 4b that is formed along the outer periphery of the bottom plate portion 4a so as to surround the mounting area of the magnetic recording disk 8.

  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.

  A shaft fixing screw hole 26 a is provided on the upper end surface of the shaft 26. The lower end of the shaft 26 is fixed to the base 4 as described later. By passing the top cover through the shaft fixing screw hole 26a and screwing the shaft fixing screw, the upper end of the shaft 26 is fixed to the top cover. The top cover is fixed to the base 4.

  Among the fixed shaft type rotating devices, 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 as described above can improve the shock resistance and vibration resistance of the rotating device. it can. In this type of rotating device, when a fluid dynamic pressure bearing is employed, there are generally two gas-liquid interfaces of the lubricant. In the rotating device 100 according to the present embodiment, instead of simply arranging the two gas-liquid interfaces and the dynamic pressure generating grooves in the direction of the rotation axis R (direction along the rotation axis R), the route of the lubricant is changed. Fold it back in the radial direction. As a result, the lubricant paths partially overlap in the direction of the rotation axis R. Therefore, even when the thickness of the rotating device 100 is specified, it is possible to increase the proportion of the portion corresponding to the dynamic pressure generating groove with respect to the entire thickness. As a result, the bearing span, which is the axial dimension of the dynamic pressure generating groove, becomes longer and the rigidity of the bearing can be improved. Further, the distance between the two gas-liquid interfaces can be reduced. As a result, the leakage of the lubricant due to the gravity acting on the lubricant and the pressure difference between the two gas-liquid interfaces can be reduced.

  2 is a cross-sectional view taken along line AA in FIG. The rotating body includes a hub 28, a cylindrical magnet 32, a rotating body-side surrounding member 105, an outer surrounding member 106, and a cap 12. The fixed body includes a base 4, a laminated core 40, a coil 42, a base-side surrounding member 102, a shaft 26, and a hub-side surrounding member 108. A lubricant 92 is continuously interposed in a part of the gap between the rotating body and the fixed body.

  The magnetic recording disk 8 is mounted on the disk mounting surface 28 a of the hub 28. The hub 28 is made of a steel material such as SUS430F having soft magnetism. The hub 28 is formed by, for example, pressing or cutting a steel plate, and is formed in a predetermined cup-like shape having a center hole along the rotation axis R. As the steel material of the hub 28, for example, stainless steel having a trade name of DHS1 supplied by Daido Steel Co., Ltd. is preferable because it has less outgas and is easy to process. Similarly, stainless steel of the product name DHS2 supplied by the company is more preferable in terms of further excellent corrosion resistance.

  The cylindrical magnet 32 is bonded and fixed to a cylindrical inner peripheral surface 28 f corresponding to the cylindrical surface inside the substantially cup-shaped hub 28. The cylindrical magnet 32 is formed using neodymium, iron, boron, or the like as a main material, and faces the salient poles of the laminated core 40 in the radial direction. The cylindrical magnet 32 is magnetized for driving with 16 poles in the circumferential direction. The surface of the cylindrical magnet 32 is rust-proofed by electrodeposition coating or spray coating.

  In the rotating device 100 according to the present embodiment, the first magnetic center 62 that is the center in the rotation axis R direction of the drive magnetization of the cylindrical magnet 32 is the center in the rotation axis R direction of the laminated core 40. Two magnetic centers 64 are positioned so as to substantially coincide with each other. This is preferable in that noise during rotation caused by the drive magnetization of the cylindrical magnet 32 and the laminated core 40 can be suppressed. The first magnetic center 62 may be located away from the second magnetic center 64 in the upward direction. Since the axial dimension of the cylindrical magnet 32 can be increased, the driving torque generated in the cylindrical magnet 32 is increased.

  In a state where the hub 28 is directed downward with respect to the base 4, the hub 28 is lowered by gravity and may be separated from the base 4 and hinder normal rotation. For this purpose, a suction plate 66 is bonded and fixed to the base 4 at a position facing the lower end of the cylindrical magnet 32. The suction plate 66 is made of, for example, a material mainly containing iron and has soft magnetism. The suction plate 66 generates a magnetic attractive force on the magnet 32. The suction plate 66 may be formed in a substantially ring shape, for example, and the inner diameter of the ring shape may be greater than or equal to the inner diameter of the cylindrical magnet 32. The ratio that the laminated core 40 receives in the magnetic flux generated by the cylindrical magnet 32 increases.

  The rotor-side surrounding member 105 is a cylindrical member that surrounds the shaft 26. The rotary member-side surrounding member 105 is formed by bonding and fixing an inner cylinder member 104 whose inner peripheral surface surrounds the shaft 26 and an outer cylinder member 103 surrounding the inner cylinder member 104 separately. A radial dynamic pressure generating groove, which will be described later, is provided on the inner peripheral surface 104 a of the inner cylinder member 104. A communication path BP that is a groove along the direction of the rotation axis R is provided on the outer periphery of the inner cylinder member 104. The communication path BP is filled with the lubricant 92 and communicates a path A and a path C described later. The communication passage BP suppresses leakage of the lubricant 92 from the gas-liquid interface by reducing the pressure difference between the passage A and the passage C. The communication path BP may be provided as a groove along the axial direction on the inner peripheral surface of the outer cylinder member 103.

  The laminated core 40 has an annular portion and twelve salient poles extending radially outward therefrom, and is fixed to the upper surface side of the base 4. The laminated core 40 is formed by laminating 5 to 10 thin electromagnetic steel plates and integrating them by caulking. 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 is provided with a through hole 4h centering on the rotation axis R of the rotating body. The base-side surrounding member 102 includes a disk portion 102 a that surrounds the base 4 side of the shaft 26 and a cylindrical portion 102 b that surrounds the rotating body-side surrounding member 105. That is, the base-side surrounding member 102 has a substantially L-shaped cross section. The outer peripheral surface 102bb of the cylindrical portion 102b is bonded and fixed to the through hole 4h. The base-side surrounding member 102 has a shaft hole 102aa centering on the rotation axis R of the rotating body, and the lower end of the shaft 26 is inserted into the shaft hole 102aa.

  The base 4 has a cylindrical protrusion 4e centered on the rotation axis R of the rotating body. The protruding portion 4e protrudes from the upper surface of the base 4 so as to surround the cylindrical portion 102b. 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 4ea of the protrusion 4e. In particular, the annular portion of the laminated core 40 is press-fitted into the protruding portion 4e or bonded and fixed by a clearance fit.

  FIG. 3 is an enlarged cross-sectional view showing the periphery of the route of the lubricant 92 in FIG. The outer cylinder member 103 is provided with an encircling recess 103bb that is recessed inward in the radial direction at an intermediate portion in the rotation axis R direction of the outer peripheral surface 103b. The outer cylinder member 103 is fixed to the hub 28 by fitting the outer peripheral surface 103 b into the hub hole 28 b of the hub 28. The hub 28 side of the outer peripheral surface 103 b of the outer cylinder member 103 is bonded to the hub hole 28 b of the hub 28. A circumferential groove is formed in a portion of the outer peripheral surface 103b fixed to the hub hole 28b. A route D of the lubricant 92 formed as a gap between the outer peripheral surface 103b and the base-side surrounding member 102 rotates with a route B of the lubricant 92 formed as a gap between the inner peripheral surface 104a and the side surface 26b of the shaft 26. Overlapping in the direction of axis R.

The lower end portion of the shaft 26 is fixed to the disk portion 102a of the base-side surrounding member 102 by an interference fit. This interference fit is realized, for example, by press-fitting the shaft 26 into the shaft hole 102aa, shrink fitting, or cooling the shaft 26 with liquid nitrogen and inserting it into the shaft hole 102aa to return to room temperature. Adhesion may be used together in this interference fit.
In the base-side surrounding member 102, the axial length of the portion where the cylindrical portion 102 b contacts the through hole 4 h is larger than the axial length of the portion where the disk portion 102 a contacts the shaft 26.

  The cylindrical part 102b may be formed separately from the disk part 102a. If the cylindrical portion 102b is formed integrally with the disc portion 102a as in the present embodiment, the number of parts can be suppressed. A gap between the inner peripheral surface 102ba of the cylindrical portion 102b and the outer peripheral surface 103b of the outer cylindrical member 103 forms the path D of the lubricant 92 described above. A gap between the first thrust surface 104d, which is the lower end surface of the inner cylinder member 104, and the first opposing surface 102c of the base-side surrounding member 102 that opposes it in the direction of the rotation axis R forms a path C of the lubricant 92. To do. The first facing surface 102c is provided on the disk portion 102a.

  A first capillary seal 110 is formed, which is a portion where the gap between the inner peripheral surface 102ba of the cylindrical portion 102b and the outer peripheral surface 103b of the outer cylindrical member 103 gradually widens upward. The first capillary seal 110 has a first gas-liquid interface 112 of the lubricant 92 and suppresses leakage of the lubricant 92 due to capillary action. The first gas-liquid interface 112 of the lubricant 92 is in contact with the inner peripheral surface 102ba of the cylindrical portion 102b and the outer peripheral surface 103b of the outer cylindrical member 103. In order to further suppress the leakage of the lubricant 92, the first capillary seal 110 may have a region where an oil repellent is applied in the vicinity of the outlet.

  For example, when the rotating device receives an impact, the lubricant 92 may scatter from the first gas-liquid interface 112. Correspondingly, a reservoir 115 which is a bag-like space having an opening at a position facing the first gas-liquid interface 112 in the direction of the rotation axis R is provided. The lubricant 92 scattered from the first gas-liquid interface 112 is caught by the pool portion 115, and leakage to the outside is suppressed. The reservoir 115 is formed between the hub 28 and the outer cylinder member 103. Specifically, it is formed in a gap between the hub hole 28b and the outer peripheral surface 103b. The reservoir 115 may be coated with an oil repellent. Leakage of the lubricant 92 is further suppressed. The reservoir 115 may be provided in a portion where the gap between the hub hole 28b and the surrounding recess 103bb gradually expands downward. The volume of the reservoir 115 is increased by the recess of the surrounding recess 103bb, and leakage to the outside can be suppressed even when a large amount of the lubricant 92 is scattered.

  The hub-side surrounding member 108 surrounds the upper side of the shaft 26 and is fixed to the shaft 26. The hub-side surrounding member 108 is a substantially annular member centered on the rotation axis R of the rotating body, and the shaft 26 is inserted into the center hole 108a thereof. The hub-side surrounding member 108 is fixed to the shaft 26 by an interference fit on the upper side of the shaft 26.

  The outer surrounding member 106 is a cylindrical member that surrounds the hub-side surrounding member 108 and is fixed to the outer cylinder member 103. The outer surrounding member 106 is bonded and fixed to the stepped portion 103 c provided on the upper side of the inner peripheral surface of the outer cylinder member 103 with an adhesive 120. The adhesive 120 is applied across the outer surrounding member 106 and the outer cylinder member 103. It may be fixed by other known methods such as press fitting. Between the outer surrounding member 106 and the hub-side surrounding member 108, a gap between the inner peripheral surface 106a of the outer surrounding member 106 and the outer peripheral surface 108b of the hub-side surrounding member 108 gradually increases upward. A second capillary seal 114, which is a portion that extends in the range, is formed. The second capillary seal 114 has a second gas-liquid interface 116 of the lubricant 92 and suppresses the leakage of the lubricant 92 due to capillary action. The second gas-liquid interface 116 of the lubricant 92 is in contact with the inner peripheral surface 106 a of the outer surrounding member 106 and the outer peripheral surface 108 b of the hub side surrounding member 108. In order to further suppress leakage of the lubricant 92, the second capillary seal 114 may have a region where an oil repellent is applied in the vicinity of the outlet thereof.

A gap between the second thrust surface 104e on the upper side of the inner cylinder member 104 and the second facing surface 108c of the hub-side surrounding member 108 facing it in the direction of the rotation axis R forms a path A of the lubricant 92. The second facing surface 108c is provided on the hub-side surrounding member 108.
The cap 12 is a disc-shaped annular member, and the outer peripheral surface is fixed to the hub hole 28 b of the hub 28. The cap 12 is provided so as to cover the second gas-liquid interface 116 and the hub-side surrounding member 108. The lower end surface of the cap 12 is in contact with the upper end surface of the outer cylinder member 103.

  A set of herringbone-shaped first radial dynamic pressure generating grooves 50 and second radial dynamic pressure generating grooves 52 spaced apart in the direction of the rotation axis R are formed on the inner peripheral surface 104a of the inner cylinder member 104. The second radial dynamic pressure generating groove 52 is formed above the first radial dynamic pressure generating groove 50. Note that at least one of the first radial dynamic pressure generating groove 50 and the second radial dynamic pressure generating groove 52 may be formed on the side surface 26b of the shaft 26 instead of the inner peripheral surface 104a.

A path B of the lubricant 92 is formed between the portion of the inner peripheral surface 104 a of the inner cylinder member 104 where the first radial dynamic pressure generating groove 50 is formed and the side surface 26 b of the shaft 26, and the rotating body side surrounding member 105. It includes a gap between a portion of the inner peripheral surface 104 a where the second radial dynamic pressure generating groove 52 is formed and the side surface 26 b of the shaft 26.
When the rotating body rotates relative to the fixed body, the first radial dynamic pressure generating groove 50 and the second radial dynamic pressure generating groove 52 respectively generate dynamic pressure in the lubricant 92 in the gap. With this dynamic pressure, the rotating body is supported in the radial direction without contacting the fixed body.

A first thrust dynamic pressure generating groove 56 having a herringbone shape or a spiral shape is formed on the lower first thrust surface 104d of the inner cylinder member 104. The first thrust dynamic pressure generating groove 56 may be formed on the first facing surface 102c of the base-side surrounding member 102 instead of the first thrust surface 104d.
A second thrust dynamic pressure generating groove 54 having a herringbone shape or a spiral shape is formed on the second thrust surface 104e on the upper side of the inner cylinder member 104. The second thrust dynamic pressure generating groove 54 may be formed on the second facing surface 108c of the hub-side surrounding member 108 instead of the second thrust surface 104e.

The path C of the lubricant 92 includes a portion of the first thrust surface 104d on the lower side of the inner cylinder member 104 where the first thrust dynamic pressure generating groove 56 is formed and the first facing surface 102c of the base-side surrounding member 102. Including gaps.
The path A of the lubricant 92 is formed between the portion of the second thrust surface 104e on the upper side of the inner cylinder member 104 where the second thrust dynamic pressure generating groove 54 is formed and the second facing surface 108c of the hub-side surrounding member 108. Including gaps.
When the rotating body rotates relative to the fixed body, the second thrust dynamic pressure generating groove 54 and the first thrust dynamic pressure generating groove 56 each generate dynamic pressure in the lubricant 92 in the gap. With this dynamic pressure, the rotating body is supported in the direction of the rotation axis R without contacting the fixed body.

  A distance L1 between the first gas-liquid interface 112 and the second gas-liquid interface 116 in the rotation axis R direction of the lubricant 92 is on the opposite side of the first radial dynamic pressure generating groove 50 from the second radial dynamic pressure generating groove 52. The distance L2 is smaller than the distance L2 from the end 50a to the end 52a of the second radial dynamic pressure generating groove 52 opposite to the first radial dynamic pressure generating groove 50.

  The lubricant 92 continuously exists from the first gas-liquid interface 112 to the second gas-liquid interface 116 through the path D, the path C, the path B, and the path A in this order. From the viewpoint of the dynamic pressure generating groove, the lubricant 92 is transferred from the first gas-liquid interface 112 to the first thrust dynamic pressure generating groove 56, the first radial dynamic pressure generating groove 50, the second radial dynamic pressure generating groove 52, and the second thrust. It exists continuously through the dynamic pressure generating groove 54 to the second gas-liquid interface 116 in this order.

  The first gas-liquid interface 112 is located closer to the second radial dynamic pressure generating groove 52 side than the end 50b of the first radial dynamic pressure generating groove 50 on the second radial dynamic pressure generating groove 52 side in the direction of the rotation axis R. In particular, the first gas-liquid interface 112 is located between the first radial dynamic pressure generating groove 50 and the second radial dynamic pressure generating groove 52 in the rotation axis R direction.

  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 12 salient poles. A driving 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.

  In the rotating device 100 according to the present embodiment, the first radial dynamic pressure generating groove 50 and the second radial dynamic pressure generating groove 52 can be further separated in the direction of the rotation axis R. Thereby, the rigidity of a bearing can be raised more. The distance L1 is smaller than the distance L2. Therefore, the first gas-liquid interface 112 and the second gas-liquid interface 116 can be made closer in the direction of the rotation axis R. Thereby, the leakage of the lubricant 92 due to the gravity acting on the lubricant 92 and the pressure difference between the air pressure at the first gas-liquid interface 112 and the air pressure at the second gas-liquid interface 116 can be reduced.

  It is desirable to fix the shaft by bonding so that the perpendicularity of the shaft with respect to the base of the joint portion between the shaft and the base in the fixed shaft type rotating device can be adjusted. However, particularly when the diameter of the shaft is small, there may be a case where sufficient bonding strength cannot be obtained by bonding.

  In the rotating device 100 according to the present embodiment, the shaft 26 is tightly fitted on the inner peripheral side of the base-side surrounding member 102, and the outer peripheral side is bonded to the base 4. Thereby, when the outer peripheral side of the base-side surrounding member 102 is bonded to the base 4, the adhesive can be cured while keeping the perpendicularity of the shaft 26 to the base 4 proper. As for the strength surface, since the shaft 26 and the base-side surrounding member 102 are tightly fitted, the strength of the joint is sufficient, and the diameter of the outer peripheral surface of the base-side surrounding member 102 is larger than the diameter of the shaft 26. Since it is large, the strength of joining by bonding the base side surrounding member 102 and the base 4 can also be sufficient.

Next, a method for manufacturing the rotating device 100 according to the embodiment will be described.
First, the base-side surrounding member 102 is coupled to the shaft 26. Further, the inner cylinder member 104 and the outer cylinder member 103 in which predetermined dynamic pressure generating grooves are formed on the inner peripheral surface 104a, the first thrust surface 104d, and the second thrust surface 104e are coupled. Next, the shaft 26 is inserted into the inner peripheral surface 104 a of the inner cylinder member 104. Next, the hub-side surrounding member 108 is coupled to a predetermined position on the upper side of the shaft 26. The outer surrounding member 106 is coupled to the step portion 103 c of the outer cylinder member 103. Hereinafter, this state is referred to as a bearing assembly. Next, the bearing assembly is exposed to a reduced pressure environment, and the air in the gap between the fixed body and the rotating body is removed. In a reduced pressure environment, a predetermined amount of lubricant 92 is attached to the gap between the outer surrounding member 106 and the hub side surrounding member 108 and the gap between the base side surrounding member 102 and the outer cylinder member 103. For example, the lubricant 92 can be discharged and adhered from a liquid injection nozzle that has been approached. Next, the bearing assembly is returned to atmospheric pressure to allow the lubricant 92 to penetrate into the bearing assembly. As a result, the lubricant 92 penetrates into the gap between the fixed body and the rotating body.

  Next, the positions of the first gas-liquid interface 112 and the second gas-liquid interface 116 of the bearing assembly in the direction of the rotation axis R are inspected. The position of the gas-liquid interface can be inspected according to the reflected light by irradiating the gas-liquid interface with a laser beam. In the rotating device 100 according to the embodiment, the first gas-liquid interface 112 and the second gas-liquid interface 116 can be viewed from the same direction in the state of the bearing assembly. Therefore, the positions of the first gas-liquid interface 112 and the second gas-liquid interface 116 can be inspected by irradiating a laser beam from the same direction. For this reason, it is not necessary to invert the bearing assembly for inspection, and the inspection apparatus becomes smaller and the labor for inspection is reduced.

  On the other hand, the cylindrical magnet 32 is bonded and fixed to the cylindrical inner peripheral surface 28f of the substantially cup-shaped hub 28. Further, the laminated core 40 with the coil 42 is bonded and fixed to the outer peripheral surface 4ea of the base 4.

  Next, the outer peripheral surface 103 b of the outer cylinder member 103 of the rotating body side surrounding member 105 is bonded and fixed to the hub hole 26 b of the hub 26. Next, the outer peripheral surface 102bb of the fixed body side surrounding member 102 is bonded and fixed to the through hole 4h. At this time, the adhesive is cured while keeping the inclination of the disk mounting surface 28a of the hub 28 with respect to the base 4 appropriate. As a result, the inclination of the disk mounting surface 28a of the hub 28 with respect to the base 4 is suppressed.

  Next, other members are mounted, a predetermined inspection is performed, and the rotating device 100 is manufactured.

  The configuration and operation of the rotating device 100 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 that various modifications can be made to combinations of the respective components, and such modifications are within the scope of the present invention.

FIG. 4 is an enlarged cross-sectional view showing the periphery of the lubricant path in an enlarged manner in the modified example 200 of the rotating device according to the present embodiment. In the modified example 200, the diameter of the portion of the outer cylinder member 103 that contacts the hub hole 28b is smaller than the diameter of the innermost peripheral portion of the first gas-liquid interface 112.
That is, the innermost peripheral portion of the first gas-liquid interface 112 is positioned radially outward from the outermost peripheral portion of the portion in contact with the hub hole 28 b of the outer cylinder member 103. As a result, before the hub 28 is fixed to the outer cylinder member 103, the first gas-liquid interface 112 can be easily seen from above. In the case of inspecting whether or not the lubricant 92 is insufficient, since it can be easily confirmed, the labor of the inspection is reduced. Further, when the position of the first gas-liquid interface 112 in the axial direction is inspected by irradiating a laser beam, the alignment of the laser beam is facilitated, and the labor of the inspection is reduced.

  Further, the upper end of the outer surrounding member 106 is positioned above the upper end of the outer cylinder member 103 in the direction of the rotation axis R. As a result, the possibility that the adhesive 120 applied across the outer cylinder member 103 and the outer surrounding member 106 flows into the capillary seal 114 beyond the upper end of the outer surrounding member 106 is reduced. The adhesive 120 may be applied over the outer surrounding member 106, the outer cylinder member 103, and the hub 28.

  In the embodiment and the modification, the case where the shaft 26 is formed separately from the base-side surrounding member 102 has been described, but the present invention is not limited to this. FIG. 5 is an enlarged cross-sectional view showing the base-side member 140 in which the shaft 26 is formed integrally with the base-side surrounding member 102 in the modification 200 of FIG. Since the number of parts is reduced, the assembly work is reduced. Even when the rotating device is formed thin, the bonding strength between the shaft 26 and the base-side surrounding member 102 can be kept high.

  In the example of FIG. 5, the base side member 140 is integrally formed by press working from a stainless material corresponding to JIS name SUS430, and then the details are finished by cutting or grinding. The base side member 140 may be formed of another material or another manufacturing method so as to satisfy a desired specification. The shaft 26 is provided with a through hole 140b by pressing. A shaft fixing screw hole 26a is formed on the upper end side of the through hole 140b. A protruding portion 140 a that expands the diameter is formed at a connection portion between the shaft 26 and the base-side surrounding member 102. When the rotating device 200 receives an impact, deformation of the connection portion can be suppressed.

  In the embodiment and the modification, the outer surrounding member 106 is described as being fixed to the inner peripheral surface of the outer cylinder member 103, but the present invention is not limited to this. For example, it may be fixed to the hub 28.

  In the embodiment and the modification, the rotating body side surrounding member 105 has been described with respect to the case where the inner cylinder member 104 and the outer cylinder member 103 are separately formed and coupled, but the present invention is not limited thereto. For example, the inner cylinder member 104 and the outer cylinder member 103 may be integrally formed.

  In the embodiment and the modification, the case where the hub 28 and the rotating body side surrounding member 105 are coupled has been described, but the present invention is not limited to this. For example, the hub 28 and the rotating body side surrounding member 105 may be integrally formed. In this case, the outer peripheral surface 28g and the inner peripheral surface 104a of the hub 28 may be continuously cut. It is easy to suppress a mismatch between the center of the outer peripheral surface 28 g of the hub 28 and the center of the inner peripheral surface 104 a of the rotating body side surrounding member 105.

  In the embodiment and the modification, the case of the so-called outer rotor type in which the cylindrical magnet 32 is located outside the laminated core 40 has been described, but the present invention is not limited to this. For example, a so-called inner rotor type 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 and the modification, the core may not be a laminated core.

  4 base, 8 magnetic recording disk, 10 data read / write section, 12 cap, 26 shaft, 28 hub, 32 cylindrical magnet, 40 laminated core, 42 coil, 50 first radial dynamic pressure generating groove, 52 second radial motion Pressure generating groove, 54 second thrust dynamic pressure generating groove, 56 first thrust dynamic pressure generating groove, 62 first magnetic center, 64 second magnetic center, 66 suction plate, 92 lubricant, 100 rotating device, 102 base side ring Enclosing member, 103 Outer cylinder member, 104 Inner cylinder member, 105 Rotating body side surrounding member, 106 Outer surrounding member, 108 Hub side surrounding member, 112 First gas-liquid interface, 116 Second gas-liquid interface, 110 First Capillary seal, 114 Second capillary seal, 120 Adhesive, BP communication path, 140 Over scan side member, 100, 200 rotating device.

Claims (11)

A fixed body having a base and a shaft fixed to the base;
A rotating body having a hub on which a recording disk is to be placed, and a rotating body-side surrounding member fixed to a hub hole provided in the hub and surrounding the shaft;
A lubricant is continuously interposed between the fixed body and the rotating body,
The lubricant has at least a first gas-liquid interface and a second gas-liquid interface;
A radial dynamic pressure generating groove for generating a radial dynamic pressure is formed on any of the surfaces of the rotating body side surrounding member and the shaft that are in contact with the lubricant,
The fixed body includes a base side surrounding member having a disk portion surrounding the base side of the shaft and a cylindrical portion surrounding the rotating body side surrounding member,
The base-side surrounding member has the disk portion fixed to the base side of the shaft by an interference fit, and the cylindrical portion is adhesively fixed to a through-hole provided in the base.
The rotary device according to claim 1, wherein the first gas-liquid interface is located in a radial gap between an inner peripheral surface of the cylindrical portion and an outer peripheral surface of the rotating body side surrounding member.   The fixed body includes a hub-side surrounding member that surrounds the hub side of the shaft and is fixed to the shaft, and the second gas-liquid interface is an outer periphery of the rotating body and the hub-side surrounding member. The rotating device according to claim 1, wherein the rotating device is located in a radial gap with the surface. The rotating body-side surrounding member has a first thrust surface that is a surface on the base side of the rotating body-side surrounding member, and a second thrust surface that is a surface opposite to the base,
The fixed body has a first opposing surface that opposes the first thrust surface in the thrust direction, and a second opposing surface that opposes the second thrust surface in the thrust direction,
A first thrust dynamic pressure groove for generating dynamic pressure in the thrust direction is formed on either the first thrust surface or the first facing surface,
The rotating device according to claim 2, wherein a second thrust dynamic pressure groove for generating a dynamic pressure in a thrust direction is formed on either the second thrust surface or the second facing surface.   The rotating device according to claim 3, wherein the first facing surface is provided on the disk portion.   5. The rotating device according to claim 3, wherein the second facing surface is provided on the hub-side surrounding member.   The rotating body includes an outer surrounding member having an inner peripheral surface surrounding the fixed body, and the second gas-liquid interface is a radial clearance between the inner peripheral surface of the outer surrounding member and the fixed body. The rotating device according to claim 1, wherein the rotating device is located.   7. The rotating device according to claim 1, wherein the hub is fixed to the rotating member-side surrounding member after the lubricant is interposed between the fixing member and the rotating member.   The rotating device according to any one of claims 1 to 7, wherein after the rotating body-side surrounding member is fixed to the hub, the fixing body-side surrounding member is fixed to the through hole.   The rotating body-side surrounding member has an inner cylindrical member whose inner peripheral surface surrounds the shaft and an outer cylindrical member that surrounds the inner cylindrical member, and is either one of the inner cylindrical member and the outer cylindrical member. 9. The rotating device according to claim 1, wherein a communication path along a rotation axis direction is provided and the lubricant is filled.   The reservoir portion, which is a space for capturing the lubricant scattered from the first gas-liquid interface, is provided in a radial gap between the outer peripheral surface of the rotating body side surrounding member and the hub hole of the hub. The rotating device according to any one of 1 to 9. A fixed body having a base and a shaft fixed to the base;
A rotating body having a hub on which a recording disk is to be placed, and a rotating body-side surrounding member fixed to a hub hole provided in the hub and surrounding the shaft;
A lubricant is continuously interposed between the fixed body and the rotating body,
A radial dynamic pressure generating groove for generating a radial dynamic pressure is formed on any of the surfaces of the rotating body side surrounding member and the shaft that are in contact with the lubricant,
The fixed body includes a base side surrounding member having a disk portion surrounding the base side of the shaft and a cylindrical portion surrounding the rotating body side surrounding member,
The base-side surrounding member is integrally formed with the shaft, and the cylindrical portion is bonded and fixed to a through-hole provided in the base.

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