JP2004245248A - Bearing mechanism, motor, and disk driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing mechanism restricted in leak of an oil by easily connecting a cap part without generating intrusion of an adhesive agent into a sleeve or into a sleeve holder part. <P>SOLUTION: This bearing mechanism 4 has a sleeve 42, in which a free end of a shaft 41 is to be inserted, the sleeve holder part 43 for holding the sleeve 42, and a nearly disk-like cap part 45, and the shaft 41 is supported by the sleeve 42 through the oil. A free end of the sleeve holder part 43 is formed with an annular projecting part 431. The peripheral part of the cap part 45 is formed with an adhesive surface 450 extended outside, while bending toward the sleeve holder part 43, outside the projecting part 431. The cap part 45 can be easily fixed to the sleeve holder part 43 through the adhesive agent 49 in the adhesive surface 450, and an opening in the free end of the sleeve holder part 43 is sealed. With this structure, intrusion of the adhesive agent 49 into the sleeve holder part 43 is prevented to prevent a leak of the oil in the bearing mechanism 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bearing mechanism having a shaft and a sleeve, a motor, and a disk drive.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a bearing mechanism having a sleeve that supports a shaft via a lubricating fluid such as oil has been employed as a bearing for a motor used in various electronic devices such as a disk drive device. In such a bearing mechanism, the shaft is inserted into the cylindrical sleeve, and the inside of the sleeve (or the sleeve holding portion that holds the sleeve) is filled with oil. Then, the opening of the sleeve (or the sleeve holding portion) corresponding to the free end side of the shaft is closed by the disk-shaped cap portion, thereby preventing the oil from flowing out.
[0003]
Note that Patent Document 1 discloses a method for preventing the oil from flowing out of the bearing mechanism by fixing the outer peripheral portion of the cap portion to the lower end surface of the sleeve holding portion by screwing. Further, Patent Literature 2 discloses a technique in which an opening of a sleeve is closed by adhesively fixing a cap portion to a sleeve to suppress oil leakage of a bearing mechanism.
[0004]
[Patent Document 1]
JP-A-2002-51518
[Patent Document 2]
JP 2001-57755 A
[0005]
[Problems to be solved by the invention]
By the way, in recent years, further miniaturization and reduction of the manufacturing cost of the motor have been demanded. However, in the method of Patent Document 1, there are structural restrictions and complicated work of screwing is required, so that these methods are used. It is difficult to meet the demand. Further, according to the method of Patent Document 2, the cap portion can be easily fixed without using a screw or the like, so that the size and the cost can be reduced. However, depending on the design of the bearing mechanism and the manufacturing procedure thereof, an adhesive may be used. May enter the inside of the sleeve and reach the bearing surface, which may adversely affect bearing performance.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to easily join a cap portion without intrusion of an adhesive into a sleeve or a sleeve holding portion, thereby preventing oil from leaking.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a bearing mechanism, wherein the shaft portion, the shaft portion is inserted, a sleeve supporting the shaft portion via a lubricating fluid, and the sleeve is inserted along a central axis. A sleeve holding portion having a substantially cylindrical shape, and a cap portion for closing one opening on the central axis of the sleeve holding portion, wherein the sleeve holding portion is arranged around the central axis around the opening. An annular projection is provided, and the cap portion is joined to the sleeve holding portion by an adhesive interposed only on the outside of the projection portion.
[0008]
According to a second aspect of the present invention, in the bearing mechanism according to the first aspect, the tip of the protruding portion abuts on the cap portion.
[0009]
A third aspect of the present invention is the bearing mechanism according to the first or second aspect, further comprising a thrust member disposed between the sleeve and the cap portion, the tip end of the shaft portion abutting.
[0010]
The invention according to claim 4 is the bearing mechanism according to any one of claims 1 to 3, further comprising a substantially annular retaining member into which a tip of the shaft portion is inserted, wherein the cap portion includes: The sleeve holding portion has an inner diameter smaller than the diameter of the opening, has an annular facing surface facing the tip of the protrusion, and the retaining member is located between the facing surface and the end surface of the sleeve. .
[0011]
The invention according to claim 5 is a bearing mechanism, wherein the shaft portion, a sleeve into which the shaft portion is inserted and which supports the shaft portion via a lubricating fluid, and one opening on a central axis of the sleeve. And a cap portion that closes the sleeve, wherein the periphery of the opening of the sleeve is a protruding portion that protrudes in an annular shape about the central axis, and the cap portion is disposed only outside the protruding portion. The tip is joined to the sleeve by an agent, and the tip of the protruding portion contacts the cap portion.
[0012]
The invention according to claim 6 is the bearing mechanism according to claim 5, further comprising a thrust member disposed between the sleeve and the cap portion, the tip end of the shaft portion abutting.
[0013]
The invention according to claim 7 is the bearing mechanism according to claim 3 or 6, wherein the thrust member is a thin plate, and has a jig insertion hole for attaching a retaining member to a tip of the shaft portion. And a sealing member for closing the jig insertion hole between the thrust member and the cap portion.
[0014]
The invention according to claim 8 is the bearing mechanism according to claim 5, further comprising a shaft fixing member connected to an end of the shaft portion opposite to the cap portion, wherein the shaft fixing member is provided. A thrust surface extending in a direction perpendicular to a central axis of the shaft portion and facing an end surface of the sleeve opposite to the protruding portion; and the shaft portion along the outer periphery of the sleeve around the central axis. A cylindrical portion protruding toward the free end side of the sleeve, a gap between an outer peripheral surface of the sleeve and an inner peripheral surface of the cylindrical portion, a gap between the thrust surface and the end surface of the sleeve, Lubricating oil is continuously present in the gap between the inner peripheral surface of the sleeve and the outer peripheral surface of the shaft portion, and the gap between the free end side end surface of the shaft portion and the cap portion, Thrust surface and the sleeve Groove for hydrodynamic generation is formed on at least one of said end faces.
[0015]
According to a ninth aspect of the present invention, in the bearing mechanism according to any one of the first to third and fifth and sixth aspects, the shaft part includes a shaft and a shaft. A disk-shaped thrust portion extending in a direction perpendicular to the central axis from an end portion, and a fluid dynamic pressure is generated on at least one of two surfaces forming a gap between the thrust portion and the cap portion. Grooves are formed, and a lubricating fluid is present in the gap.
[0016]
According to a tenth aspect of the present invention, there is provided a motor, comprising the bearing mechanism according to any one of the first to ninth aspects, and a drive mechanism for rotating the shaft portion relative to the sleeve.
[0017]
The invention according to claim 11 is a disk drive device, wherein a housing for accommodating a disk-shaped recording medium for recording information, and wherein the recording medium is fixed inside the housing and rotates the recording medium. And an access means for writing or reading information to or from the recording medium.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a longitudinal sectional view showing a motor unit 1 according to the first embodiment of the present invention. The motor unit 1 has a rotor unit 2 as a rotating assembly and a stator unit 3 as a fixed assembly. The rotor unit 2 is rotatably supported by the bearing mechanism 4 with respect to the stator unit 3.
[0019]
The rotor section 2 has a cup member 21 opened to the stator section 3 and formed of a magnetic material. A multi-pole magnetized annular field magnet 22 is attached to the inner peripheral surface of the cup member 21, and the cup member 21 serves as a yoke for the field magnet 22. A shaft fixing portion 23 to which one end of the shaft 41 of the bearing mechanism 4 is fixed is provided at the center of the cup member 21, and a recording disk 24 a on which various information is recorded is provided in an outer cylindrical portion of the shaft fixing portion 23. The recording disk 24a is detachably magnetically attracted and attached by the disk fixing magnet 23a placed thereon and accommodated inside the shaft fixing portion 23.
[0020]
The stator portion 3 has an annular base plate 31, and a sleeve holding portion 43 of the bearing mechanism 4 is integrally formed at the center of the base plate 31. The sleeve holding portion 43 projects toward the rotor portion 2 and has a cylindrical shape centered on a predetermined central axis 40, and the armature 32 faces the field magnet 22 on the outer peripheral surface of the sleeve holding portion 43. Provided. An external current supply circuit is connected to the armature 32, and the supplied current is controlled, so that the driving mechanism including the field magnet 22 and the armature 32 generates a torque, and the torque is generated around the shaft 41. To rotate the rotor section 2 with respect to the stator section 3. The magnetic center of the armature 32 is located at a position shifted axially downward from the magnetic center of the field magnet 22.
[0021]
The bearing mechanism 4 is formed of an oil-impregnated porous metal body and has a cylindrical sleeve 42 centered on the central axis 40. The free end side of the shaft 41 is inserted into the sleeve 42, whereby the shaft 41 is inserted. Are rotatably supported via oil. The sleeve 42 is inserted into and fixed to the sleeve holding portion 43 along the central axis 40. An annular retaining member 44 is attached to the free end of the shaft 41. Thus, when the rotor unit 2 moves in the direction away from the stator unit 3, the upper surface of the retaining member 44 comes into contact with the lower end surface of the sleeve 42 to lock the separation between the shaft 41 and the sleeve 42. Is done.
[0022]
The bearing mechanism 4 further includes a substantially disk-shaped cap portion 45 and an annular oil seal 46. The cap portion 45 allows the lower opening of the sleeve holding portion 43 (ie, the free end of the shaft 41). The opening on the upper side of the sleeve holding portion 43 is closed by the oil seal 46. The inside of the sleeve holding portion 43 is filled with oil, and the cap portion 45 and the oil seal 46 prevent the oil from flowing out of the sleeve holding portion 43.
[0023]
FIG. 2 is an enlarged view showing the vicinity of the cap portion 45. As shown in FIG. 2, a protruding portion 431 that protrudes in an annular shape around the central axis 40 is formed around the lower opening of the sleeve holding portion 43. The protruding portion 431 is in contact with the upper surface of the cap portion 45 at the tip. Outside the protruding portion 431, a flat surface 431a is provided, which is in contact with the adhesive surface 450 extending outward while bending toward the sleeve holding portion 43 side of the cap portion 45. The cap portion 45 is joined to the flat surface 431a of the sleeve holding portion 43 with the adhesive 49 interposed at the adhesive surface 450. Therefore, the cap portion 45 has a shallow dish shape, and the protruding portion 431 comes into contact with a bent portion that bends from the inner bottom surface to the outside.
[0024]
A thrust washer 471 made of resin (for example, PEEK (polyetheretherketone)) and a metal (for example, stainless steel) are formed between the sleeve 42 and the cap portion 45 via the retaining member 44. A thin plate-shaped thrust plate 472 and a seal member 48 made of resin or rubber are provided.
[0025]
FIG. 3 is a diagram showing a thrust washer 471 superimposed on a thrust plate 472. As shown in FIG. 3, a plurality of through-holes 473 used when assembling the bearing mechanism 4 described later is formed in the disk-shaped thrust plate 472, and the plurality of through-holes 473 are formed at predetermined positions of the thrust plate 472. It is arranged at equal intervals on the circumference of the radius. The thrust plate 472 is fitted inside the above-mentioned protruding portion 431, and is plastically deformed inside this protruding portion 431 to be caulked and fixed. The thrust washer 471 is composed of a disk-shaped base portion and a plurality of protrusions extending outward from the outer edge of the base portion. The protrusions are provided at equal intervals on the periphery without overlapping the through holes 473. , Are arranged approximately at the center of the thrust plate 472. The thrust washer 471 is merely mounted on the thrust plate 472 and is not fixed. However, even when the thrust washer 471 moves in the radial direction, the protrusion contacts the inner peripheral surface of the sleeve holding portion 43, so that the tip of the shaft 41 is Does not come off the base portion, and does not move significantly because the shaft 41 is pressed in the axial direction. The seal member 48 is attached to the lower surface of the thrust plate 472. Since the through hole 473 is closed by the seal member 48 as shown in FIG. 2, the oil inside the sleeve holding portion 43 is prevented from leaking through the through hole 473. In addition, although there is a possibility that the oil is soaked and the sticking property is reduced and the sealing member 48 is peeled off, the sealing member 48 is covered with the cap portion 45 outside the sealing member 48. Leakage can be prevented. Even if the oil passes through the seal member 48 and reaches the cap portion 45, since the cap portion 45 has a shallow dish shape, oil leakage can be prevented.
[0026]
When the motor unit 1 rotates, the magnetic center of the armature 32 and the magnetic center of the field magnet 22 are shifted from each other, as described above. A magnetic attraction force acts in the thrust direction (that is, the direction of the central axis 40) during the rotation. Thus, the tip of the shaft 41 abuts on the thrust washer 471, and the shaft 41 is stably supported in the thrust direction (see FIG. 2). At this time, in the motor portion 1, the thrust support portion 470 constituted by the thrust washer 471 and the thrust plate 472 acts as a damper, and the sealing member 48 also functions as a damper. Vibration is efficiently suppressed.
[0027]
FIG. 4 is a diagram for explaining how the bearing mechanism 4 is assembled. When the bearing mechanism 4 is assembled, first, the sleeve 42 is press-fitted into the sleeve holding portion 43 and fixed. At this time, the sleeve 42 is accurately positioned with respect to a reference surface (surface denoted by reference numeral 91 in FIG. 4) fixed to the sleeve holding portion 43. Subsequently, the retaining member 44, the thrust washer 471, and the thrust plate 472 are sequentially inserted into the sleeve holding portion 43 from the opening on the side opposite to the sleeve 42, and the outer peripheral surface of the thrust plate 472 fits inside the protruding portion 431, The protrusion 431 is in contact with a flat surface inside the protrusion 431, and the protrusion 431 is plastically deformed inward and fixed by caulking. At this time, the thrust washer 471 is positioned and mounted so as not to overlap the through hole 473 of the thrust plate 472 as described above, and the thrust plate 472 is fixed (see FIG. 3). The positioning of the thrust washer 471 and the thrust plate 472 is performed by, for example, an operator using tweezers or the like, or by using a dedicated jig.
[0028]
Next, the shaft 41 is inserted into the sleeve 42 in the direction of arrow 93. Then, a dedicated jig 92 is inserted into the through hole 473 of the thrust plate 472 from below to lift the retaining member 44 so that the distance between the upper end surface of the retaining member 44 and the lower end surface of the sleeve 42 becomes a distance a. The retaining member 44 is accurately supported on the reference surface 91, and the tip of the shaft 41 is pressed into the retaining member 44.
[0029]
When the retaining member 44 is press-fitted, the jig 92 is removed, and the seal member 48 having an adhesive is fixed from the outside (that is, the lower side) of the thrust plate 472 (see FIG. 2). Below the seal member 48, the cap portion 45 is further fixed to the flat surface 431 a of the sleeve holding portion 43 by applying the adhesive 49 to the adhesive surface 450. At this time, since the upper surface of the cap portion 45 and the tip of the protruding portion 431 are in contact with each other, the cap portion 45 is easily positioned with respect to the direction along the central axis 40, and the adhesive 49 is placed inside the protruding portion 431 Intrusion (that is, toward the central shaft 40) is prevented. Note that the adhesive 49 may be applied to the flat surface 431a of the sleeve holding portion 43 facing the bonding surface 450, and the cap portion 45 may be attached.
[0030]
As described above, in the bearing mechanism 4 of the motor unit 1, the sleeve holding unit 43 has the annular projecting portion 431 around one opening on the central shaft 40, and the cap portion 45 is formed only outside the projecting portion 431. Is easily joined to the sleeve holding portion 43 by the adhesive 49 interposed therebetween, and one opening of the sleeve holding portion 43 is closed. Accordingly, it is possible to prevent the adhesive 49 from entering the inside of the sleeve holding portion 43 and to suppress the oil from flowing out from one opening side of the sleeve holding portion 43. As a result, it is possible to prevent the rotation of the motor unit 1 from being hindered, and to improve the reliability of the motor unit 1.
[0031]
Further, in a disk drive described later using the motor unit 1, resonance generated in a recording disk or the like due to vibration in the bearing mechanism 4 is suppressed by the damper effect of the thrust support 470 and the seal member 48, and the disk drive Reliability can be improved. It is also possible to change the frequency of vibration in the bearing mechanism 4 by changing the thickness or material of the thrust support portion 470 and the seal member 48, and to more effectively suppress the resonance occurring in the recording disk or the like.
[0032]
FIG. 5 is a longitudinal sectional view showing a motor section 1a according to the second embodiment of the present invention. In the motor unit 1a shown in FIG. 5, the rotor unit 2 has a cup member 21 opening toward the stator unit 3, and a multi-pole magnetized annular field magnet 22 is provided on the inner peripheral surface of the cup member 21. It is attached. At the center of the cup member 21, a cylindrical shaft fixing portion 23 protruding toward the stator portion 3 is formed, and a disk mounting portion 24 (for example, a CD-ROM, a DVD, or the like is mounted) is provided at one end. Is fixed to the cup member 21 by being inserted into the shaft fixing portion 23. An annular groove 411 is formed at the free end of the shaft 41.
[0033]
The stator portion 3 has an annular base plate 31, and a peripheral wall portion 33 protruding toward the rotor portion 2 is formed at the center of the base plate 31. A cylindrical sleeve holding portion 43 that is formed by press working and that has a predetermined center axis 40 as a center is inserted into and fixed to the peripheral wall portion 33. An armature 32 that constitutes a driving mechanism of the motor unit 1a is mounted on the outer peripheral surface of the sleeve holding unit 43 together with the field magnet 22. The sleeve holder 43 does not necessarily need to be formed by press working.
[0034]
A cylindrical sleeve 42 made of an oil-impregnated porous metal body is inserted into the sleeve holding portion 43 along the central axis 40, and the outer peripheral surface of the sleeve 42 and the inner peripheral surface of the sleeve holding portion 43 contact each other. By contact, the sleeve 42 is fixed to the sleeve holding portion 43. The side of the sleeve holding section 43 opposite to the rotor section 2 is formed as an annular projection 431 projecting below the base plate 31 and centered on the central axis 40, and an annular annular section is provided inside the projection 431. A retaining member 44 is provided. The retaining member 44 is an annular plate having an outer diameter substantially equal to the inner diameter of the sleeve holding portion 43 and an inner diameter smaller than the outer diameter of the shaft 41. The free end side of the shaft 41 is inserted into the sleeve 42 and the retaining member 44, and the groove 411 of the shaft 41 and the retaining member 44 constitute a retaining mechanism. The tip of the shaft 41 is easily inserted into the retaining member 44.
[0035]
The bearing mechanism 4 having the shaft 41 and the sleeve 42 has a substantially bowl-shaped cap portion 45 that opens on the fixed end side (that is, the rotor portion 2 side), and the cap portion 45 is located on the free end side of the sleeve holding portion 43. It is fixed to the sleeve holding portion 43 by adhesive so as to close the opening. The cap portion 45 has an inner diameter smaller than the diameter of the opening on the free end side of the sleeve holding portion 43 and has an annular facing surface 452 facing the tip of the protruding portion 431. It is fixed by being sandwiched between the end face and the opposing face 452 of the cap part 45. A disc-shaped thrust plate 47 made of resin (for example, PEEK) or the like is provided at a position of the cap portion 45 facing the tip of the shaft 41.
[0036]
An annular oil seal 46 is provided on the fixed end side of the sleeve holding portion 43, and the opening on the fixed end side of the sleeve holding portion 43 is closed by the oil seal 46. The oil impregnated in the sleeve 42 is prevented from leaking out of the sleeve holding portion 43 by the oil seal 46 and the cap portion 45.
[0037]
In the motor unit 1a of FIG. 5, similarly to the motor unit 1 of FIG. 4, the magnetic center of the field magnet 22 and the magnetic center of the armature 32 are axially displaced from each other. At times, a magnetic attractive force acts between the rotor section 2 and the stator section 3 in the thrust direction. As a result, the tip of the shaft 41 slidably contacts the thrust plate 47, and the shaft 41 is stably supported in the thrust direction. Further, the shaft 41 is supported in a radial direction by a sleeve 42 via oil.
[0038]
FIG. 6 is a diagram for explaining how the cap portion 45 is fixed to the sleeve holding portion 43. When closing the opening of the sleeve holding portion 43 (opening on the free end side of the shaft 41) in the bearing mechanism 4, as shown in FIG. 6, after the adhesive 49 is applied to the outer peripheral surface of the protruding portion 431, The cap part 45 is fitted into the sleeve holding part 43. At this time, since the inner peripheral surface on the opening side of the cap portion 45 is fitted into the outer peripheral surface of the protruding portion 431 while substantially abutting on the outer peripheral surface, the excess of the applied adhesive 49 is arranged along the outer peripheral surface of the protruding portion 431. And move upward. Then, as shown in FIG. 7, the opposing surface 452 of the cap portion 45 abuts on the end surface of the protruding portion 431 so that the cap portion 45 is accurately positioned with respect to the sleeve holding portion 43 in the direction along the central axis 40. Fixed.
[0039]
As described above, in the bearing mechanism 4 of the motor portion 1a, the cap portion 45 is easily joined to the sleeve holding portion 43 with the adhesive 49 interposed only outside the outer peripheral surface of the protrusion 431 of the sleeve holding portion 43, One opening of the sleeve holding portion 43 is closed. This prevents the adhesive 49 from entering the inside of the sleeve holding portion 43 and adversely affecting the rotation of the motor portion 1a, and suppresses the oil from flowing out of the bearing mechanism 4.
[0040]
Further, in the conventional bearing mechanism similar to the structure of the bearing mechanism 4, the sleeve holding portion is formed with high precision by cutting or the like, and the cap portion is fixed at the swaged portion formed on the inner peripheral surface side of the sleeve holding portion. However, in the bearing mechanism 4 of FIG. 5, it is necessary to appropriately fix the cap portion 45 even in the case of the sleeve holding portion 43 (for example, the sleeve holding portion 43 formed by press working) whose shape accuracy is inferior to the conventional one. And the manufacturing cost of the motor unit can be reduced.
[0041]
FIG. 8 is a longitudinal sectional view showing a motor unit 1b according to the third embodiment of the present invention. In the motor section 1b of FIG. 8, the rotor section 2 has a substantially bowl-shaped rotor hub 21a opened to the stator section 3 side, and the shaft 41 of the bearing mechanism 4 is protruded to the opening side at the center of the rotor hub 21a. It is formed integrally. The rotor hub 21a is made of a magnetic material such as iron, and includes a disk portion 211 extending in a direction perpendicular to the central axis 40 of the shaft 41, and a cylindrical portion 212 protruding toward the stator portion 3 on the outer periphery of the disk portion 211. Is done. On the outer peripheral surface of the rotor hub 21a (that is, the outer peripheral surface of the cylindrical portion 212), a disk mounting portion 24 protruding outward is formed, and a multipolar magnetized annular field magnet 22 is attached. An annular magnetic shield plate 25 made of a ferromagnetic material is fixed between the disk mounting portion 24 and the field magnet 22.
[0042]
The stator portion 3 has an annular base plate 31, and a cylindrical peripheral wall portion 33 protruding toward the rotor portion 2 is formed at the center of the base plate 31. An armature (not shown) is provided on the outer peripheral portion of the base plate 31 so as to face the outside of the field magnet 22, and a driving mechanism of the motor unit 1 b is configured together with the field magnet 22. On the base plate 31, an annular magnetic body 34 is provided at a position facing the field magnet 22.
[0043]
The bearing mechanism 4 has a substantially cylindrical sleeve 42 centered on the central shaft 40 and a cylindrical shaft outer tube 412, and the shaft 41 is inserted into and fixed to the shaft outer tube 412. In the motor part 1b, the shaft 41 and the shaft outer cylinder part 412 constitute a shaft unit 410 that is the center of rotation of the motor part 1b. The free end side of the shaft unit 410 is inserted into the sleeve 42 and is rotatably supported.
[0044]
The sleeve 42 has an annular projection 421 projecting toward the free end and centered on the central axis 40. The projection 421 is inserted into a bottomed cylindrical cap 45 formed by press working. And fixed by bonding. At this time, since an adhesive is applied to the outer peripheral surface of the protrusion 421 and inserted into the cap portion 45, an excess of the applied adhesive moves upward along the outer peripheral surface of the protrusion 421. . Then, when the end surface of the protrusion 421 and the bottom surface 451 of the cap portion 45 (that is, the surface facing the free end side end surface of the shaft unit 410) are in contact with each other, as shown in FIG. Are accurately positioned in the direction along the central axis 40 and are joined by the adhesive 49, and the opening on the free end side of the sleeve 42 is closed by the cap portion 45. The sleeve 42 to which the cap portion 45 is fixed is inserted into the peripheral wall portion 33 and fixed to the base plate 31. Note that the cap portion 45 does not necessarily need to be formed by press working.
[0045]
In the motor portion 1b of FIG. 8, between the end surface 422 of the sleeve 42 on the disk portion 211 side and the lower surface of the disk portion 211 facing the end surface 422, the inner peripheral surface 423 of the sleeve 42 and the outer peripheral surface of the shaft unit 410 ( That is, gaps 51, 52, and 53 are provided between the outer peripheral surface of the shaft outer cylindrical portion 412) and between the bottom surface 451 of the cap portion 45 and the end surface on the free end side of the shaft unit 410, respectively. These gaps 51 to 53 are dynamic pressure bearings continuously filled with oil, and constitute a so-called full-fill structure bearing mechanism. In the full-filled bearing mechanism, air does not intervene inside the bearing, so abnormal contact between the shaft and sleeve caused by air bubbles generated in the oil and oil leakage due to expansion of the air inside the bearing are suppressed. A high-performance dynamic pressure bearing is realized.
[0046]
Further, an annular flange portion 424 projecting outward in the circumferential direction is formed on the upper portion of the outer peripheral surface of the sleeve 42, and the outer peripheral surface of the flange portion 424 is an inclined surface 425 whose radius gradually decreases downward. As a result, the gap 54 between the inclined surface 425 and the inner peripheral surface of the cylindrical portion 212 that protrudes toward the free end along the outer periphery of the sleeve 42 gradually increases downward. A taper seal in which the oil interface has a meniscus shape due to the tension is formed, and continuous outflow of oil from the gap 51 is prevented.
[0047]
On the opposing thrust surfaces of the gap 51 (either one of the surfaces may be formed), a groove for generating a pressure inwardly inward in the circumferential direction with respect to the oil when the rotor portion 2 rotates is formed. 51 constitutes a thrust dynamic pressure bearing portion. Further, the shaft outer cylinder portion 412 is provided with a through hole 413 that continues from the gap 51 to the gap 53, whereby the oil pressure in the gap 53 becomes equal to the oil pressure increased in the gap 51. The gap 53 serves as a thrust hydrostatic bearing.
[0048]
Grooves (for example, herringbone grooves provided at the top and bottom in the axial direction) for generating a fluid dynamic pressure in the oil are formed on the surfaces of the gap 52 facing each other. A pressure bearing is configured.
[0049]
A retaining member 44 protruding toward the central shaft 40 outside the gap 54 is fixed to the inner peripheral surface of the cylindrical portion 212. The inner diameter of the annular retaining member 44 is smaller than the outer diameter of the lower part of the flange portion 424. Thus, in the motor portion 1b, even when the rotor portion 2 moves in the direction away from the stator portion 3, the retaining member 44 comes into contact with the lower surface of the flange portion 424 so that the shaft unit 410 comes off the sleeve 42. Is prevented.
[0050]
When the motor 1b is driven, a force for floating the rotor 2 (that is, a thrust force) is generated by the thrust dynamic pressure bearing by the gap 51 and the thrust hydrostatic bearing by the gap 53 as described above. At this time, the magnetic attractive force and the thrust force acting between the magnetic body 34 and the field magnet 22 are balanced, and the support of the rotor unit 2 in the thrust direction (axial direction) is stabilized.
[0051]
As described above, in the bearing mechanism 4 of the motor portion 1b, the annular protrusion 421 centered on the central axis 40 is formed around one opening of the sleeve 42, and the cap portion 45 is provided at the tip of the protrusion 421. By abutting, positioning is performed with high accuracy and easily in the direction along the central axis 40. Further, the cap portion 45 is joined to the sleeve 42 by an adhesive 49 interposed only on the outer peripheral surface side of the protruding portion 421, and the opening of the sleeve 42 is closed, so that the outflow of oil is suppressed.
[0052]
On the other hand, in a conventional bearing mechanism having a structure similar to that of the bearing mechanism 4, a caulked portion is formed on the inner peripheral surface side of the lower portion of the sleeve, and the cap portion is caulked at the caulked portion and fixed by bonding. In the bearing mechanism 4 described above, the adhesive 49 can be prevented from intervening inside the sleeve 42 by the above-described structure, and the thickness can be further reduced. As a result, the performance of the bearing mechanism 4 can be maximized, and the thinned motor portion 1b can be appropriately rotated, and the reliability of the motor portion 1b can be improved.
[0053]
FIG. 10 is a longitudinal sectional view showing a motor unit 1c according to the fourth embodiment of the present invention. In the motor section 1c shown in FIG. 10, the rotor section 2 has a substantially bowl-shaped rotor hub 21a opened to the stator section 3 side, and the multi-pole rotor hub 21a is attached to the open end face via a cylindrical yoke 221. The magnetized annular field magnet 22 is fixed. One end of a shaft 41, which will be described later, is fixed to the center of the rotor hub 21a, and a disk mounting portion 24 is formed on the outer peripheral surface of the rotor hub 21a.
[0054]
The stator portion 3 has an annular base plate 31, and a cylindrical peripheral wall portion 33 protruding toward the rotor portion 2 is formed on an inner peripheral portion of the base plate 31. An armature 32 is attached to the outer peripheral surface of the peripheral wall 33 so as to face the field magnet 22, and the armature 32 and the field magnet 22 constitute a driving mechanism of the motor unit 1 c.
[0055]
The bearing mechanism 4 has a cylindrical sleeve 42 centered on a predetermined central axis 40, and the free end side of the shaft 41 is inserted into the sleeve 42. The tip of the shaft 41 is a disc-shaped thrust plate 414 that extends in a direction perpendicular to the central axis 40, and the upper surface of the thrust plate 414 faces the lower end surface of the sleeve 42. The sleeve 42 is inserted into a concentric cylindrical sleeve holding portion 43, and an annular oil seal 46 is fixed to the fixed end side of the sleeve holding portion 43.
[0056]
A cylindrical protruding portion 431 centering on the central axis 40 is provided on the free end side end surface of the sleeve holding portion 43. The bearing mechanism 4 has a bottomed cylindrical cap portion 45 formed by cutting or the like. The cap portion 45 is fixed to the protrusion 431 of the sleeve holding portion 43. At this time, the cap portion 45 is fitted after the adhesive is applied to the outer peripheral surface of the protruding portion 431, and therefore, the excess adhesive applied moves upward along the outer peripheral surface of the protruding portion 431. . When the tip of the protrusion 431 contacts the bottom surface of the cap 45, the sleeve holder 43 and the cap 45 are accurately positioned in the direction along the central axis 40. As shown in FIG. The sleeve holding portion 43 and the cap portion 45 are joined by an adhesive 49 located only on the side opposite to the central axis 40 of the sleeve. The sleeve holding portion 43 to which the cap portion 45 is fixed is inserted into the peripheral wall portion 33 and fixed to the base plate 31.
[0057]
As shown in FIG. 10, between the lower surface 415 of the thrust plate 414 and the bottom surface of the concave portion of the cap portion 45 facing the lower surface 415, between the upper surface of the thrust plate 414 and the lower end surface of the sleeve 42, and Gaps 55, 56, and 57 are formed between the inner peripheral surface 423 and the outer peripheral surface of the shaft 41, respectively.
[0058]
Each of the gaps 55 to 57 is continuously filled with oil to constitute a dynamic pressure bearing mechanism having the same full-fill structure as described above, and also has two surfaces forming the gap 57 (that is, the inner peripheral surface 423 of the sleeve 42, Further, at least one of the outer peripheral surfaces of the shaft 41 is formed with a groove for generating a fluid dynamic pressure (for example, a herringbone groove or the like provided vertically above and below in the axial direction). A radial dynamic pressure bearing portion that supports in the direction is configured.
[0059]
Further, at least one of two thrust surfaces forming the gap 55 (that is, the lower surface 415 of the thrust plate 414 and the bottom surface of the concave portion of the cap portion 45) has a groove for generating fluid dynamic pressure (for example, herring). Bone groove, etc.) are formed, and a first thrust dynamic pressure bearing portion is configured. Similarly, a groove for generating fluid dynamic pressure is formed on at least one of the two thrust surfaces forming the gap 56, and a second thrust dynamic pressure bearing portion is configured. In the motor portion 1c, the shaft 41 is stably supported in the thrust direction by the first thrust dynamic pressure bearing portion and the second thrust dynamic pressure bearing portion.
[0060]
As described above, in the bearing mechanism 4 of the motor portion 1c, the sleeve holding portion 43 is inserted into the cap portion 45 along the central axis 40, and is easily formed by the adhesive 49 interposed on the opposite side of the projecting portion 431 from the central axis 40. Joined. Thereby, it is possible to prevent the adhesive 49 from leaking into the inside of the sleeve holding portion 43 and adhering to the shaft 41 and the cap portion 45 to hinder the rotation of the motor portion 1c. Oil is prevented from leaking from the motor portion 1c, and the reliability of the motor portion 1c can be improved.
[0061]
In the motor portion 1c, since the cap portion 45 plays a role as a thrust bearing portion, high-precision positioning of the cap portion 45 is required, but the cap portion 45 is fixed by abutting on the tip of the protruding portion 431. Therefore, positioning can be performed accurately in the direction along the central axis 40, and bearing performance is ensured.
[0062]
Next, a disk drive device having a motor will be described with reference to FIG. In the disk drive device 80, the inside of the housing 81 is a clean space with extremely little dust or dirt, and a disk drive motor 82 on which a disk-shaped recording medium 83 for storing information is mounted is fixed. I have. Further, inside the housing 81, a head moving mechanism is disposed as information access means for reading and writing information on the recording medium 83. The head moving mechanism includes a head 86 for reading and writing information on the recording medium 83, and a head 86. And an actuator section 84 for moving the head 86 and the arm 85 to required positions on the recording medium 83.
[0063]
By using the motor units 1 and 1a to 1c described in the above embodiment as the disk drive motor 82 of the disk drive device 80, desired rotation accuracy and stable operation are realized. At the same time, the reliability of the disk drive device 80 can be ensured. The disk drive device 80 is not limited to a so-called hard disk device, and may be a device for driving an optical disk, a magneto-optical disk, or the like.
[0064]
As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments, and various modifications are possible.
[0065]
In the first, second, and fourth embodiments, a protruding portion is provided around the opening on the free end side of the sleeve 42 so as to protrude in an annular shape around the central axis 40, and the cap portion 45 is It may be joined to the sleeve 42 by an adhesive that abuts only on the outside of the protruding portion while being in contact with the tip. Further, in the third embodiment, a substantially cylindrical sleeve holding portion into which the sleeve 42 is inserted along the central axis 40 is provided, and a circle provided around the opening on the free end side of the sleeve holding portion. The cap portion 45 may be joined to the sleeve holding portion by an adhesive interposed only on the outside of the annular protrusion, and the opening on the free end side of the sleeve holding portion may be closed.
[0066]
In the first and second embodiments, the bearing mechanism 4 may be a bearing mechanism utilizing fluid dynamic pressure. In the third and fourth embodiments, the sleeve 42 is made of an oil-impregnated porous material. It may be a sliding bearing or the like made of a porous metal body.
[0067]
In the third and fourth embodiments, similarly to the first and second embodiments, a thrust plate (or a thrust support) is disposed between the sleeve 42 and the cap 45. The shaft 41 (or the shaft unit 410) may be supported in the thrust direction by the thrust plate.
[0068]
In the above embodiment, the shaft 41 is fixed to the rotor portion 2 and rotates with respect to the sleeve 42. For example, as shown in FIG. 13, the sleeve 42 is fixed to the rotor portion 2 (or is integrally formed). ), And may rotate with respect to the shaft 41. In the motor portion shown in FIG. 13, an annular protrusion 431 centering on the central axis 40 is provided around the upper opening of the sleeve 42, and a substantially bowl-shaped cap portion 45 opening downward is provided. It is joined to the sleeve 42 by an adhesive interposed only outside the portion 431. Similarly, in the motor section having the sleeve holding section, the sleeve and the sleeve holding section may be fixed to the rotor section and rotate with respect to the shaft.
[0069]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, a cap part can be easily joined without an adhesive invading the inside of a sleeve or a sleeve holding part, and while the leakage of a lubricating fluid can be suppressed, the adhesive invades the inside of a bearing. Without adversely affecting bearing performance.
[0070]
According to the second and fifth aspects of the present invention, the cap portion can be accurately joined to the sleeve or the sleeve holding portion in the direction along the central axis.
[0071]
According to the third, sixth, eighth, and ninth aspects, the shaft portion can be stably supported in the thrust direction.
[0072]
Further, according to the invention of claim 4, separation of the shaft portion and the sleeve can be prevented.
[0073]
Further, according to the invention of claim 7, vibration of the bearing mechanism can be suppressed, and leakage of the lubricating fluid from the jig insertion hole can be prevented.
[0074]
According to the tenth aspect, the reliability of the motor can be improved, and in the eleventh aspect, the reliability of the disk drive device can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a motor unit according to a first embodiment.
FIG. 2 is an enlarged view showing the vicinity of a cap portion.
FIG. 3 is a diagram showing a thrust washer superimposed on a thrust plate.
FIG. 4 is a diagram for explaining how to assemble a motor unit.
FIG. 5 is a longitudinal sectional view showing a motor unit according to a second embodiment.
FIG. 6 is a view for explaining a state in which a cap section is fixed to a sleeve holding section.
FIG. 7 is an enlarged view showing the vicinity of a cap portion.
FIG. 8 is a longitudinal sectional view showing a motor unit according to a third embodiment.
FIG. 9 is an enlarged view showing the vicinity of a cap.
FIG. 10 is a longitudinal sectional view showing a motor unit according to a fourth embodiment.
FIG. 11 is an enlarged view showing the vicinity of a cap portion.
FIG. 12 is a diagram showing a disk drive device.
FIG. 13 is a longitudinal sectional view showing another example of the motor unit.
[Explanation of symbols]
1,1a-1c motor
4 Bearing mechanism
21a Rotor hub
22 Field magnet
32 armature
40 center axis
41 shaft
42 sleeve
43 Sleeve holding part
44 retaining member
45 Cap
47,414,472 Thrust plate
48 Sealing member
49 adhesive
51-57 gap
80 disk drive
81 Housing
83 recording media
84 Actuator section
85 arm
86 head
211 disk
212 cylindrical part
415, 422, 423, 425, 431a, 450-452 planes
421,431 Projection
470 Thrust support
473 Through hole

Claims (11)

A bearing mechanism,
Shaft part,
A sleeve in which the shaft portion is inserted, and which supports the shaft portion via a lubricating fluid;
A substantially cylindrical sleeve holding portion into which the sleeve is inserted along a central axis,
A cap portion for closing one opening on the central axis of the sleeve holding portion,
With
The sleeve holding portion has a protruding portion that protrudes in an annular shape around the central axis around the opening,
The bearing mechanism, wherein the cap portion is joined to the sleeve holding portion by an adhesive interposed only outside the projecting portion. The bearing mechanism according to claim 1, wherein
A bearing mechanism, wherein a tip of the protruding portion contacts the cap portion. The bearing mechanism according to claim 1 or 2,
A bearing mechanism, further comprising a thrust member disposed between the sleeve and the cap portion, the thrust member contacting a tip of the shaft portion. The bearing mechanism according to any one of claims 1 to 3, wherein
Further comprising a substantially annular retaining member into which the tip of the shaft portion is inserted,
The cap portion has an inner diameter smaller than the diameter of the opening of the sleeve holding portion, and has an annular facing surface facing the tip of the protruding portion,
The bearing mechanism, wherein the retaining member is located between the facing surface and an end surface of the sleeve. A bearing mechanism,
Shaft part,
A sleeve in which the shaft portion is inserted, and which supports the shaft portion via a lubricating fluid;
A cap portion for closing one opening on the central axis of the sleeve,
With
The periphery of the opening of the sleeve is a protrusion that protrudes in an annular shape around the central axis,
A bearing mechanism, wherein the cap portion is joined to the sleeve by an adhesive interposed only on the outside of the protrusion, and a tip of the protrusion contacts the cap portion. The bearing mechanism according to claim 5, wherein
A bearing mechanism, further comprising a thrust member disposed between the sleeve and the cap portion, the thrust member contacting a tip of the shaft portion. The bearing mechanism according to claim 3 or 6, wherein
The thrust member is a thin plate, and has a jig insertion hole when attaching a retaining member to the tip of the shaft portion,
A bearing mechanism, further comprising a seal member between the thrust member and the cap portion for closing the jig insertion hole. The bearing mechanism according to claim 5, wherein
Further comprising a shaft fixing member connected to an end of the shaft portion opposite to the cap portion,
The shaft fixing member,
A thrust surface that extends in a direction perpendicular to the central axis of the shaft portion and faces an end surface opposite to the protrusion of the sleeve;
A cylindrical portion protruding toward the free end side of the shaft portion along the outer periphery of the sleeve around the center axis;
Has,
A gap between the outer peripheral surface of the sleeve and the inner peripheral surface of the cylindrical portion, a gap between the thrust surface and the end surface of the sleeve, and a gap between the inner peripheral surface of the sleeve and the outer peripheral surface of the shaft portion. Lubricating oil is continuously present in the gap between the cap portion and the end face of the shaft portion on the free end side,
A bearing mechanism, wherein a groove for generating fluid dynamic pressure is formed on at least one of the thrust surface and the end surface of the sleeve. The bearing mechanism according to any one of claims 1 to 3, and claims 5 and 6,
The shaft portion,
Shaft and
A disk-shaped thrust portion extending in a direction perpendicular to a central axis from an end of the shaft on the cap portion side,
Has,
A bearing mechanism, wherein a groove for generating a fluid dynamic pressure is formed in at least one of two surfaces forming a gap between the thrust portion and the cap portion, and a lubricating fluid is present in the gap. . A motor,
A bearing mechanism according to any one of claims 1 to 9,
A drive mechanism for rotating the shaft portion relative to the sleeve,
A motor comprising: A disk drive,
A housing for accommodating a disk-shaped recording medium for recording information,
The motor according to claim 10, wherein the motor is fixed inside the housing and rotates the recording medium.
An access unit for writing or reading information on or from the recording medium.

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