JP2009197996A - Fluid bearing device, spindle motor having the same and recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid bearing device, a spindle motor having the same and a recording and reproducing device, enabling extended service life thereof, by holding a sufficient quantity of lubricating fluid supplied to a bearing part in a microscopic clearance, while satisfying a request for thinning. <P>SOLUTION: This fluid bearing device 20 rotates a rotation side member such as a rotor hub 15 with a shaft 12 inserted into a bearing hole 11a of a sleeve 11 in a rotatable state as the rotational center. The fluid bearing device 20 includes a plurality of substantially annular ring-shaped tapered seal parts (a first tapered seal part 21 and a second tapered seal part 22) for holding the lubricating fluid 26 outside in the radial direction of the sleeve 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrodynamic bearing device mounted on a hard disk drive or the like, a spindle motor including the same, and a recording / reproducing apparatus.

  In recent years, spindle motors mounted on disk drive devices such as hard disk drive devices (hereinafter referred to as HDDs) have developed hydrodynamic bearings (hereinafter referred to as fluid) that can achieve low NRRO (Non-Repetitive Run Out) and low noise by non-contact rotation. It is shown as a bearing device).

  In such a hydrodynamic bearing device, in order to improve the angular rigidity of the hydrodynamic bearing device, it is desirable to employ a configuration in which the length of the radial bearing portion formed in the gap between the shaft and the sleeve is secured as long as possible. . On the other hand, since there is a demand for thinning the spindle motor, a configuration is required in which the thickness of the radial bearing portion is ensured while the thickness of the hydrodynamic bearing device is not increased.

  For example, in Patent Document 1, the length of the radial bearing portion is secured by providing a taper seal portion in the gap between the inner peripheral surface of the protrusion of the hub and the outer peripheral surface of the sleeve, A spindle motor is disclosed in which a gap between opposing surfaces is used as a reservoir for a lubricating fluid.

Further, Patent Document 2 discloses a conical motion in which a pair of retaining members are provided on the sleeve and the shaft bush in order to form the reference gap between the sleeve and the shaft bush with high accuracy with a simple configuration. A pressure bearing device is disclosed.
JP 2006-17153 A (published on January 19, 2006) JP 2005-61464 A (published March 10, 2005)

  However, the conventional spindle motor and the like have the following problems.

  That is, in the apparatus disclosed in the above publication, the lubrication supplied to the bearing is satisfied even when a radial bearing having a length necessary for ensuring sufficient angular rigidity is satisfied while satisfying the demand for thinning. There is a possibility that sufficient fluid cannot be secured. In this case, if the amount of lubricating fluid decreases due to evaporation, leakage to the outside, etc., a sufficient amount of lubricating fluid is not supplied to the bearing portion, resulting in malfunction and prolonging the life of the device. It becomes difficult to plan.

  An object of the present invention is to provide a hydrodynamic bearing device capable of extending the life of the device by satisfying a demand for thinning and holding a sufficient amount of lubricating fluid supplied to the bearing portion in a minute gap. Another object of the present invention is to provide a spindle motor and a recording / reproducing apparatus including the same.

  A hydrodynamic bearing device according to a first invention includes a shaft, a sleeve, a hub, and a taper seal portion. The sleeve has a bearing hole in which the shaft is loaded so as to be rotatable via a lubricating fluid. The hub is attached to the rotating body that rotates about the shaft so as to cover the open end side of the bearing hole in the sleeve. The plurality of substantially annular tapered seal portions are disposed between a part of the hub and the sleeve on the radially outer side of the sleeve, and hold the lubricating fluid.

  Here, a plurality of substantially annular taper seal portions are provided between a portion of a hub (such as a hanging portion) fixed to the rotating body side (shaft or sleeve) on the radially outer side of the sleeve and the sleeve. That is, when the hydrodynamic bearing device is viewed from the axial direction, a plurality of substantially annular tapered seal portions are arranged in the radial direction.

  Here, the tapered seal portion extends from the interface of the lubricating fluid to the back side so that the lubricating fluid filled in a minute gap including the bearing portion formed between the shaft and the sleeve does not leak to the outside. A plurality of substantially annular members having a center around the shaft are arranged in the radial direction, the portion holding the lubricating fluid by capillary force (surface tension) by narrowing the size of the gap.

  As a result, a plurality of interfaces in contact with the outside air in the radial direction can be provided radially outside the sleeve, so a radial bearing formed in the gap between the shaft and the sleeve is provided as close as possible to the hub. It can be a sufficient length. Therefore, the angular rigidity of the hydrodynamic bearing device can be improved. In addition, by providing a plurality of tapered seal portions, the surface tension acting on the lubricating fluid can be increased, and the lubricating fluid can be reliably held within the minute gap. Therefore, it is possible to prevent the lubricating fluid from leaking when an impact or the like is applied, and to avoid a decrease in the lubricating fluid. Furthermore, since a plurality of taper seal portions are provided, the volume of the portion for storing the lubricating fluid excluding the bearing portion can be increased. For this reason, it is possible to ensure a sufficient amount of the lubricating fluid supplied to the bearing portion and extend the life of the fluid bearing device.

  A hydrodynamic bearing device according to a second invention is the hydrodynamic bearing device according to the first invention, wherein the hydrodynamic bearing device is attached to the outer peripheral surface of the sleeve, and a plurality of taper seal portions are respectively provided on the inner peripheral side and the outer peripheral side. A substantially annular ring seal member is further provided.

  Here, in order to form the plurality of tapered seal portions described above, a substantially annular ring seal member attached to the outer peripheral surface of the sleeve is used.

  Thereby, for example, a first taper seal portion (second taper seal portion) is formed in the gap between the inner peripheral surface of the ring seal member and the sleeve, and the outer peripheral surface of the ring seal member and a part of the hub ( A second taper seal portion (first taper seal portion) can be formed in the gap between the bottom portion and the drooping portion. Therefore, by adding only the ring seal member, it is possible to easily form a plurality of substantially circular tapered seal portions arranged in the radial direction.

  A hydrodynamic bearing device according to a third aspect of the invention is the hydrodynamic bearing device according to the second aspect of the invention, wherein the ring seal member is substantially from the facing surface of the substantially annular outer peripheral surface and the sleeve to the sleeve toward the sleeve. A first taper seal portion is formed between the vertically extending drooping portion. Further, the ring seal member forms a second taper seal portion between the substantially annular inner peripheral surface and the outer peripheral surface of the sleeve.

  Here, the 1st taper seal part and the 2nd taper seal part are provided in the outer peripheral surface side and inner peripheral surface side of the ring seal member attached with respect to the outer peripheral surface of a sleeve, respectively.

  Thereby, the taper seal part arrange | positioned by radial direction can be easily formed with the simple structure which only added the ring seal member.

  A hydrodynamic bearing device according to a fourth invention is the hydrodynamic bearing device according to the second or third invention, wherein the ring seal member has a substantially L-shaped cross section along a radial direction of a substantially annular member. It has a shape.

  Here, as the shape of the ring seal member, a substantially annular member having a substantially L-shaped cross section along the radial direction is used.

  Thereby, the gap | interval which each functions as a taper seal part can be provided in the outer peripheral side and inner peripheral side of a ring seal member by arrange | positioning so that a substantially L-shaped bending part may face the outer peripheral surface of a sleeve. . Specifically, the gap between the outer peripheral surface of the ring seal member and the hanging portion of the hub, and the gap between the inner peripheral surface of the ring seal member and the sleeve can be used as a taper seal portion. Therefore, a plurality of taper seal portions can be formed along the radial direction with a simple configuration.

  A hydrodynamic bearing device according to a fifth aspect of the present invention is the hydrodynamic bearing device according to any one of the second to fourth aspects of the present invention, wherein the ring seal member has a bench hole for communicating the taper seal portion with the outside air. is doing.

  Here, one or a plurality of bench holes are provided in the ring seal member attached to the outer peripheral surface of the sleeve to communicate the taper seal portion with the outside air.

  Here, for example, one or a plurality of the bench holes may be provided along the circumferential direction on the bottom surface or the outer peripheral surface of the ring seal member having a substantially L-shaped cross section.

  Thereby, when an impact is applied to the hydrodynamic bearing device, it is possible to avoid the periphery of the taper seal portion from being sealed. Therefore, the bubbles mixed in the lubricating fluid can be smoothly discharged to the outside air.

  A hydrodynamic bearing device according to a sixth invention is the hydrodynamic bearing device according to the first invention, wherein the hydrodynamic bearing device is attached to the inner peripheral surface of the hub, and a plurality of taper seal portions are provided on the inner peripheral side and the outer peripheral side. Further provided are substantially annular ring seal members formed respectively.

  Here, in order to form the plurality of tapered seal portions described above, a substantially annular ring seal member attached to the inner peripheral surface of the hub is used.

  Thereby, for example, a first taper seal portion (second taper seal portion) is formed in the gap between the inner peripheral surface of the ring seal member and the outer peripheral surface of the sleeve, and the outer peripheral surface of the ring seal member and the hub A second taper seal portion (first taper seal portion) can be formed in a gap between a part (the hanging portion). Therefore, by adding only the ring seal member, it is possible to easily form a plurality of substantially circular tapered seal portions arranged in the radial direction.

  Further, since the ring seal member is fixed to the inner peripheral surface side of the hub, the ring seal member also rotates with the hub. For this reason, the interface on the inner peripheral surface side of the interface between the two lubricating fluids respectively formed on the inner and outer peripheral surfaces of the ring seal member is sandwiched between the rotation side member and the fixed side member, so that the state tends to fluctuate. It becomes. Therefore, compared to the configuration in which the ring seal member is fixed to the outer peripheral surface side of the sleeve, the interface that is likely to fluctuate moves from the outer peripheral surface side to the inner peripheral surface side of the ring seal member. The applied centrifugal force can be reduced and leakage of the lubricating fluid can be prevented.

  A hydrodynamic bearing device according to a seventh aspect of the present invention is the hydrodynamic bearing device according to the sixth aspect of the present invention, wherein the ring seal member is substantially from the facing surface of the substantially annular outer peripheral surface to the sleeve in the hub toward the sleeve side. A first taper seal portion is formed between the vertically extending drooping portion. Further, the ring seal member forms a second taper seal portion between the substantially annular inner peripheral surface and the outer peripheral surface of the sleeve.

  Here, the 1st taper seal part and the 2nd taper seal part are provided in the outer peripheral surface side and inner peripheral surface side of the ring seal member attached with respect to the internal peripheral surface of a hub, respectively.

  Thereby, the taper seal part arrange | positioned by radial direction can be easily formed with the simple structure which only added the ring seal member.

  A hydrodynamic bearing device according to an eighth invention is the hydrodynamic bearing device according to the sixth or seventh invention, wherein the ring seal member has a substantially L-shaped cross section along a radial direction of a substantially annular member. It has a shape.

  Here, as the shape of the ring seal member, a substantially annular member having a substantially L-shaped cross section along the radial direction is used.

  As a result, by arranging the substantially L-shaped bent portion so as to face the inner peripheral surface of the hub, a gap functioning as a taper seal portion is provided on each of the outer peripheral side and the inner peripheral side of the ring seal member. Can do. Specifically, the gap between the outer peripheral surface of the ring seal member and the hanging portion of the hub, and the gap between the inner peripheral surface of the ring seal member and the sleeve can be used as a taper seal portion. Therefore, a plurality of taper seal portions can be formed along the radial direction with a simple configuration.

  A hydrodynamic bearing device according to a ninth invention is the hydrodynamic bearing device according to any one of the sixth to eighth inventions, wherein the ring seal member has a bench hole for communicating the taper seal portion with the outside air. is doing.

  Here, the ring seal member attached to the inner peripheral surface of the hub is provided with one or a plurality of bench holes that allow the taper seal portion and the outside air to communicate with each other.

  Here, for example, one or a plurality of the bench holes may be provided along the circumferential direction on the bottom surface or the outer peripheral surface of the ring seal member having a substantially L-shaped cross section.

  Thereby, when an impact is applied to the hydrodynamic bearing device, it is possible to avoid the periphery of the taper seal portion from being sealed. Therefore, the bubbles mixed in the lubricating fluid can be smoothly discharged to the outside air.

  A hydrodynamic bearing device according to a tenth invention is the hydrodynamic bearing device according to the first to ninth inventions, wherein the plurality of tapered seal portions are along a direction in which the diameter increases toward the hub side in the axial direction. Has been placed.

  Here, the plurality of tapered seal portions formed on the outer side in the radial direction of the sleeve are formed in such a direction that the diameter increases toward the hub side in the axial direction.

  Here, as a configuration for forming the taper seal portion in the above-described direction, for example, a ring seal member including an inclined surface whose diameter increases toward the hub side is arranged, or the inner peripheral surface of the hub or the outer peripheral surface of the sleeve May be formed obliquely along the above direction.

  Thereby, even when the centrifugal force generated when the rotation-side member including the hub rotates is applied to the lubricating fluid in the vicinity of the tapered seal portion, the lubricating fluid is moved to the hub side depending on the shape of the tapered seal portion. be able to. As a result, even when centrifugal force is applied to the lubricating fluid, leakage of the lubricating fluid from the interface of the taper seal portion can be effectively suppressed, and the life of the hydrodynamic bearing device can be extended.

  A hydrodynamic bearing device according to an eleventh invention is the hydrodynamic bearing device according to any one of the first to tenth inventions, further comprising a fluid reservoir formed in a gap between the hub and the sleeve. ing.

  Here, in a shaft rotation type hydrodynamic bearing device, a fluid that fills a minute gap including between the shaft and the sleeve and supplies the lubricating fluid supplied to the bearing portion between the opposed surfaces of the hub and the sleeve. A reservoir is provided. In other words, a dynamic pressure generating groove is not provided between the opposed surfaces of the hub and the sleeve, and the fluid is used as a fluid reservoir.

  Thereby, the lubricating fluid supplied with respect to a bearing part is fully securable in the micro clearance gap between a taper seal part and a radial bearing part. Therefore, even when the lubricating fluid decreases due to evaporation or the like, it is possible to avoid a decrease in bearing performance and to extend the life of the hydrodynamic bearing device.

  A hydrodynamic bearing device according to a twelfth aspect of the present invention is the hydrodynamic bearing device according to the eleventh aspect of the present invention, wherein the hub has a recess that expands a space used as a fluid reservoir portion on the surface facing the sleeve. Yes.

  Accordingly, in the configuration in which the gap between the hub and the sleeve is used as a fluid reservoir, for example, the size (volume) of the fluid reservoir is provided by providing a recess by digging or the like in the surface on the hub side. ) Can be easily expanded. Therefore, it is possible to configure a hydrodynamic bearing device capable of sufficiently storing the lubricating fluid supplied to the bearing portion.

  A hydrodynamic bearing device according to a thirteenth invention is the hydrodynamic bearing device according to the eleventh invention, wherein the sleeve has a recess having a different axial height in the radial direction as a fluid reservoir.

  Accordingly, in the configuration in which the gap between the hub and the sleeve is used as a fluid reservoir, for example, by providing a recess in the radial direction by digging into a part of the sleeve, the size of the fluid reservoir is increased. The thickness (volume) can be easily increased. Therefore, it is possible to configure a hydrodynamic bearing device capable of sufficiently storing the lubricating fluid supplied to the bearing portion.

  A fluid dynamic bearing device according to a fourteenth invention is the fluid dynamic bearing device according to any one of the first to thirteenth inventions, further comprising a radial bearing portion and a thrust bearing portion. At least one of the radial bearing portion and the thrust bearing portion has an asymmetric groove that imparts a circulation force to the lubricating fluid.

  Here, an asymmetrical dynamic pressure generating groove is formed in a bearing portion (radial bearing portion and / or thrust bearing portion) formed in a minute gap including a gap between the shaft and the sleeve.

  As a result, the lubricating fluid that has flowed into the bearing portion is given a circulating force that moves along the minute gap in a desired direction. As a result, the bubbles can be smoothly discharged to the outside air by circulating the lubricating fluid mixed with the bubbles together with the bubbles.

  A hydrodynamic bearing device according to a fifteenth aspect of the present invention is the hydrodynamic bearing device according to any one of the first to fourteenth aspects of the present invention, wherein a spiral groove formed on either one of the opposed surfaces of the hub and the sleeve is provided. In addition.

  Here, in the shaft rotation type hydrodynamic bearing device, a spiral groove for guiding bubbles toward the radially outer side is provided on one of the opposed surfaces of the hub and the sleeve.

  As a result, when the bubbles mixed in the lubricating fluid move to the minute gap between the hub and the sleeve when an impact is applied, the bubbles are smoothly guided radially outward by the spiral groove. Thus, the air can be discharged from the taper seal portion disposed on the radially outer side to the outside air.

  A hydrodynamic bearing device according to a sixteenth invention is the hydrodynamic bearing device according to any one of the first to fifteenth inventions, wherein the gap between the facing surfaces of the hub and the sleeve is directed radially outward. growing.

  Here, in the shaft rotation type hydrodynamic bearing device, the minute gap between the opposed surfaces of the hub and the sleeve is formed so that the size thereof changes in the radial direction. Specifically, the minute gap is formed such that the gap increases toward the outside in the radial direction.

  Thereby, it can suppress by a capillary force (surface tension) of a micro clearance gap that a lubricating fluid moves toward a radial direction outer side by the centrifugal force provided when the rotary body side containing a hub rotates. As a result, it is possible to prevent the lubricating fluid from moving outward in the radial direction by the action of the centrifugal force and leaking from the taper seal portion.

  A spindle motor according to a seventeenth aspect includes the hydrodynamic bearing device according to any one of the first to sixteenth aspects.

  As a result, the length of the radial bearing portion can be sufficiently secured while satisfying the demand for thinning as a whole device, and the lubricating fluid supplied to the bearing portion can be sufficiently stored to extend the life. A possible spindle motor can be obtained.

  A recording / reproducing apparatus according to an eighteenth aspect includes the spindle motor according to the seventeenth aspect.

  As a result, the length of the radial bearing portion can be sufficiently secured while satisfying the demand for thinning as a whole device, and the lubricating fluid supplied to the bearing portion can be sufficiently stored to extend the life. A possible recording / reproducing apparatus can be obtained.

  According to the fluid dynamic bearing device of the present invention, the length of the radial bearing portion is sufficiently secured while satisfying the demand for thinning the entire device, and the lubricating fluid supplied to the bearing portion is sufficiently stored. To extend the service life.

(Embodiment 1)
A spindle motor 10 equipped with a hydrodynamic bearing device 20 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5B.

[Configuration of the entire spindle motor 10]
As shown in FIG. 1, the spindle motor 10 according to the present embodiment includes a hydrodynamic bearing device 20 including a rotor magnet 16, a stator 17 around which a plurality of coils are wound, a base 18, a rotor hub (hub) 15, and the like. Yes.

  The rotor magnet 16 is attached by being multipolarly magnetized in the circumferential direction on the inner peripheral surface side of the rotor hub 15, and generates a rotating magnetic field between the opposing stator 17 by sequentially energizing the coils. Thus, the rotor hub 15 is rotated about the shaft 12.

  The base 18 is provided with motor parts such as a stator 17 and a rotor magnet 16. A substantially cylindrical portion is provided with a hollow cylindrical portion 18a for fixing the sleeve 11 and a hole 18b opened in the center thereof. A stator 17 formed of a core around which a coil is wound is fixed to a portion of the base 18 where the hole 18b is formed by adhesion or the like.

  Since the hydrodynamic bearing device 20 rotates the magnetic recording disk about the shaft 12, the rotating side member including the rotor hub 15 on which the magnetic recording disk is mounted is made smoothly with respect to the fixed side member (sleeve 11 or the like). Rotate. The configuration of the hydrodynamic bearing device 20 will be described in detail later.

[Configuration of Fluid Bearing Device 20]
1 and 2A, the hydrodynamic bearing device 20 includes a sleeve 11, a shaft 12, a thrust flange 13, a thrust plate 14, a rotor hub 15, a ring seal member 19, first and second taper seal portions ( Taper seal portions) 21 and 22 and a fluid reservoir portion 23.

(Sleeve 11)
The sleeve 11 has a bearing hole 11a, is formed of a metal material such as iron, iron alloy, copper, or copper alloy, and is fixed to the base 18. Further, as shown in FIG. 2A, the sleeve 11 has a communication hole 11b formed along the axial direction and a radial formed on the inner peripheral surface side of the bearing hole 11a facing the outer peripheral surface of the shaft 12. And a dynamic pressure generating groove (radial bearing portion) 11c.

  The communication hole 11b is a through hole formed so as to penetrate the sleeve 11 in the axial direction, and lubricates within the gap including the bearing portion by the flow of the lubricating fluid 26 formed by the radial dynamic pressure generating groove 11c and the like. The fluid 26 is circulated.

  The radial dynamic pressure generating groove 11c is a herringbone-shaped dynamic pressure generating groove, and generates dynamic pressure when the shaft 12 on the rotating side rotates. Further, the radial dynamic pressure generating groove 11c has an asymmetric herringbone shape in the axial direction. For example, as shown in FIG. 2B, one or both of the two radial dynamic pressure generating grooves 11c arranged in the axial direction are formed so that α> β. For this reason, the flow of the lubricating fluid 26 is formed in a desired direction in the gap (radial bearing portion) between the sleeve 11 and the shaft 12 (in the case of FIG. 2B, the radial fluid in FIG. 2A). A flow that circulates downward from the top is also formed in the bearing portion). Thereby, the lubricating fluid 26 can be efficiently circulated in the hydrodynamic bearing device 20, and the bubbles mixed in the lubricating fluid 26 can be effectively discharged to the external space.

  Further, between the shaft 12 including the radial dynamic pressure generating groove (radial bearing portion) 11c (see FIG. 2) and the thrust dynamic pressure generating groove (thrust bearing portion) 13c, the bearing hole 11a of the sleeve 11, and the thrust flange 13 A gap between the sleeve 11 and between the thrust flange 13 and the thrust plate 14 is filled with a lubricating fluid 26. The lubricating fluid 26 generates a pumping pressure when the rotating side of the shaft 12 or the like rotates.

  The radial dynamic pressure generating groove 11c may be formed not on the sleeve 11 side but on the shaft 12 side. Further, the radial dynamic pressure generating groove 11c may have two spiral shapes (substantially C-shaped) instead of the herringbone shape. Further, it may be a conical bearing having the characteristics of both a radial bearing portion and a thrust bearing portion.

(Shaft 12)
The shaft 12 is a member made of a metal material and having a cylindrical outer peripheral surface having a diameter of about 2.0 to 4.0 mm (for example, a columnar member or a cylindrical member), and is formed in the bearing hole 11a. Inserted in a rotatable state. Further, a disc-shaped thrust flange 13 having a circular opening at the center portion is joined to the lower end portion of the shaft 12 by caulking, press fitting, welding, or the like. The thrust flange 13 may be integrally formed with the shaft 12. Since the shaft 12 is used as an axis of rotation center, for example, a material with relatively high hardness such as SUS is used and is processed by cutting and polishing.

(Thrust flange 13)
The thrust flange 13 is a substantially disk-shaped member, and is fixed to or integrally with the shaft 12 as described above. The thrust flange 13 is housed in a space surrounded by the sleeve 11 and a thrust plate 14 that is a thrust bearing member.

  The lower surface of the thrust flange 13 faces the thrust plate 14, and a thrust dynamic pressure generating groove 14c is formed. The peripheral portion of the upper surface of the thrust flange 13 is opposed to a step portion formed below the sleeve 11. A thrust dynamic pressure generating groove 13 c is formed on the upper surface of the thrust flange 13 that faces the sleeve 11. The thrust dynamic pressure generating groove 13c may be formed in a stepped portion of the opposing sleeve 11. Further, when the rotor hub 15 is attracted downward in FIG. 1 by a magnet or the like, the thrust dynamic pressure generating groove may not be necessary.

(Thrust plate 14)
The thrust plate 14 is a substantially disk-shaped member attached so as to cover the lower opening of the hydrodynamic bearing device 20, and a thrust dynamic pressure generating groove 14c is formed on the upper surface thereof.

  The surface on which the thrust dynamic pressure generating groove 14c is formed is not limited to the configuration of the present embodiment, and may be formed on any one of the opposing surfaces while ensuring a gap in the axial direction. . That is, the thrust dynamic pressure generating grooves 13 c and 14 c may be formed on either the lower surface of the thrust flange 13 or the upper surface of the thrust flange 13.

(Rotor hub 15)
The rotor hub 15 has a substantially cup shape and has a through hole at a substantially central portion. The upper end portion of the shaft 12 is fixed to the through hole by a press-fit adhesive method or the like. A rotor magnet 16 of the spindle motor 10 is attached to the rotor hub 15 and faces the stator 17 in the radial direction. A magnetic recording disk (not shown) is fixed to the rotor hub 15 and constitutes a magnetic recording / reproducing device such as a hard disk device as a whole together with other components. Further, the rotor hub 15 has a hanging portion 15 a that protrudes along the axial direction from the surface on the side facing the sleeve 11.

(Ring seal member 19)
As shown in FIG. 2, the ring seal member 19 is a substantially annular member having a substantially L-shaped cross section along the radial direction, and contacts the step portion 11 e formed at the upper portion of the outer peripheral surface of the sleeve 11. It is fixed by bonding in contact. Further, as shown in the cross-sectional view taken along the line AA in FIG. A bench hole 19a for communicating with the external space is provided. Further, the ring seal member 19 forms first and second taper seal portions 21 and 22 on the outer peripheral surface side and the inner peripheral surface side, respectively.

  As shown in FIG. 3, one or more bench holes 19a may be provided along the circumferential direction (see FIG. 6 (a) and FIG. 7 (a)). ). Further, the bench hole 19a may be provided on the bottom surface side (bent portion) of the substantially L-shaped cross section, or may be provided on the side surface side substantially along the axial direction. The position of the bench hole 19a is preferably arranged as far away from the communication hole 11b as possible. For example, as shown in FIG. 3, the position of the communication hole 11 b and the position of the bench hole 19 a are provided at opposite positions around the shaft 12. This is because, when an impact or vibration is applied, the lubricating fluid 26 may be pushed out through the communication hole 11 b, and the pushed lubricating fluid is the liquid level of the first taper seal portion 21 or the second taper seal portion 22. This is because it is possible to change the height and leak from the bench hole 19a. However, the size of the ring seal member 19 is usually determined so that it does not leak from the bench hole 19a even if such a situation occurs. The same applies to FIG. 12 of another embodiment (D) described later.

(First taper seal portion 21)
The first taper seal portion 21 is a substantially annular seal portion formed between the outer peripheral surface of the ring seal member 19 and the facing surface of the hanging portion 15a of the rotor hub 15, and is a lubricating fluid facing the external space. 26 first interfaces are formed.

  The first taper seal portion 21 is formed in a state where the surface on the ring seal member 19 side is inclined with respect to the inner peripheral surface of the hanging portion 15a of the rotor hub 15 along the substantially vertical direction. More specifically, the first taper seal portion 21 forms a gap that narrows from the first interface of the lubricating fluid 26 toward the back side. Thereby, the lubricating fluid 26 filled in the gap formed between the rotor hub 15 and the shaft 12 and the sleeve 11 can be held by capillary force.

(Second taper seal portion 22)
The second taper seal portion 22 is a substantially annular seal portion formed between the inner peripheral surface of the ring seal member 19 and the facing surface of the sleeve 11, and is disposed opposite to the bottom surface of the ring seal member 19. The second interface of the lubricating fluid 26 is formed.

  The second taper seal portion 22 is formed in a state where the outer peripheral surface of the sleeve 11 is inclined with respect to the surface on the ring seal member 19 side along the substantially vertical direction. More specifically, the second taper seal portion 22 forms a gap that becomes narrower from the second interface of the lubricating fluid 26 toward the back side. Thereby, the lubricating fluid 26 filled in the gap formed between the rotor hub 15 and the shaft 12 and the sleeve 11 can be held by capillary force.

  In addition, since the 2nd interface formed in the 2nd taper seal part 22 is opposingly arranged by the bottom face of the ring seal member 19, most does not face external space. However, the second interface and the external space are communicated with each other by a bench hole 19a formed in a part of the ring seal member 19 described above. Thus, when an impact is applied to the hydrodynamic bearing device 20, the relative position of the sleeve 11 with respect to the rotor hub 15 and the like is prevented from moving and the second interface becomes a sealed space. It is possible to prevent the balance of the interface from being lost. Further, since the space in contact with the second taper seal portion 22 communicates with the outside only through the bench hole 19a, the evaporated particles of the lubricating fluid 26 are likely to stay and the evaporation amount can be suppressed.

(Fluid reservoir 23)
The fluid reservoir 23 is formed in a gap between the opposed surfaces of the rotor hub 15 and the sleeve 11. Thereby, the radial bearing part including the radial dynamic pressure generating groove 11c and the opening part of the lubricating fluid 26 can be separated from each other in the radial direction, and a sufficient distance between them can be secured. Therefore, the axial length of the radial bearing portion is sufficiently secured to improve the angular rigidity of the fluid bearing device 20, and the lubricating fluid 26 supplied to the radial bearing portion and the like is sufficiently stored in the fluid reservoir portion 23. Can do. As a result, even when the amount of the lubricating fluid 26 gradually decreases due to evaporation, leakage, or the like, a sufficient amount of the lubricating fluid 26 supplied to the bearing portion is secured to extend the life of the device. Can do.

<Oil lubrication method to the hydrodynamic bearing device 20>
In the present embodiment, the lubricating fluid 26 is injected into the predetermined gap in the hydrodynamic bearing device 20 mounted on the spindle motor 10 having the above-described configuration by the following procedure.

  That is, first, as shown in FIG. 4, the hydrodynamic bearing device 20 is placed in the vacuum chamber 50 with the rotor hub 15 facing down.

Next, the vacuum chamber 50 is evacuated.
Next, as shown in FIGS. 4 and 5, a predetermined amount of lubrication is applied to the vicinity of the upper surface of the ring seal member 19, that is, the first and second taper seal portions 21 and 22 using an oiling device 51 such as a dispenser. Lubricate the fluid 26. At this time, a fluid movement preventing portion such as a step 15aa protruding in the axial direction is provided on the outer peripheral side portion of the drooping portion 15a of the rotor hub 15 so that the lubricated lubricating fluid 26 does not spill out radially outward. It is preferable to be provided. The fluid movement preventing portion may be a portion coated with an oil repellent other than the step 15aa.

  Next, by opening the vacuum chamber 50 from the vacuum state to the atmospheric pressure, as shown in FIG. 5, the lubricated lubricating fluid 26 is filled into a predetermined gap in the hydrodynamic bearing device 20 due to a pressure difference. To go. At this time, the lubricating fluid 26 lubricated on the ring seal member 19 is directly filled into the first taper seal portion 21. On the other hand, the second taper seal portion 22 is filled with the lubricating fluid 26 moved from the first taper seal portion 21 or moved through the bench hole 19a. Further, the lubricating fluid 26 filled in the second taper seal portion 22 is filled in a fluid reservoir portion 23 formed in a gap between the opposed surfaces of the rotor hub 15 and the sleeve 11, and then the sleeve 11 and the shaft 12, A radial bearing portion, a thrust bearing portion, etc. formed in a gap between the thrust flange 13 and the like are also filled.

  Here, the lubricating fluid 26 filled in the predetermined gap in the hydrodynamic bearing device 20 is adjusted in the height position of the interface at the first taper seal portion 21 facing the external space. Thereby, it can adjust by the balance with the interface in the 1st taper seal part 21 to the height position of the interface in the 2nd taper seal part 22 in which most are interrupted | blocked by the ring seal member 19 from external space. .

[Features of the hydrodynamic bearing device 20]
(1)
In the hydrodynamic bearing device 20 of the present embodiment, as shown in FIGS. 1 and 2, the shaft 12 inserted in a rotatable state in the bearing hole 11a of the sleeve 11 is used as a center of rotation, and the rotation side of the rotor hub 15 etc. Rotate the member. The hydrodynamic bearing device 20 includes a plurality of substantially annular taper seal portions (the first taper seal portion 21 and the second taper seal portion 22) that hold the lubricating fluid 26 outside the sleeve 11 in the radial direction. .

  Thereby, compared with the conventional hydrodynamic bearing device which has only one substantially annular taper seal part, the storage volume of the lubricating fluid can be increased by providing a plurality of taper seal parts. In addition, the surface tension acting on the lubricating fluid 26 can be increased by having a plurality of tapered seal portions. Therefore, the lubricant fluid 26 can be prevented from being reduced due to evaporation, leakage to the outside, or the like by storing more lubricant fluid 26 than before while holding the lubricant fluid 26 firmly in the taper seal portion. .

  Further, by providing the plurality of taper seal portions on the radially outer side than the sleeve 11, the radial bearing portion formed in the gap between the sleeve 11 and the shaft 12 can be made long.

  As a result, a sufficient amount of the lubricating fluid 26 is firmly held in the gap including the bearing portion, thereby extending the life of the hydrodynamic bearing device 20 and ensuring the sufficient length of the radial bearing portion. The hydrodynamic bearing device 20 having excellent rigidity can be obtained.

(2)
The hydrodynamic bearing device 20 of the present embodiment further includes a substantially annular ring seal member 19 attached along the outer peripheral surface of the sleeve 11 as shown in FIG. Tapered seal portions (first and second taper seal portions 21 and 22) are formed on the outer peripheral surface side of the ring seal member 19, respectively.

  Thereby, the taper seal parts 21 and 22 can be easily provided on the radially outer side of the sleeve 11 only by adding the ring seal member 19. Specifically, the first taper seal portion 21 is disposed in the gap between the inner peripheral surface of the rotor hub 15 (the hanging portion 15 a) and the outer peripheral surface of the ring seal member 19, and the inner periphery of the outer periphery of the sleeve 11 and the ring seal member 19. The 2nd taper seal part 22 can be formed in the clearance gap between a surrounding surface, respectively.

(3)
In the hydrodynamic bearing device 20 of the present embodiment, as shown in FIG. 2 and the like, as described above, the ring seal member 19 attached to provide a plurality of taper seal portions on the radially outer side of the sleeve 11 has the radial direction. The cross section along the line has a substantially L-shaped shape.

  As a result, a substantially L-shaped bent portion of the sleeve 11 is formed in a state where a portion along the axial direction of the substantially L-shaped shape is spaced from the outer peripheral surface of the sleeve 11 and the hanging portion 15 a of the rotor hub 15. It can fix in the state contacted to the outer peripheral surface. As a result, it is possible to provide a plurality of tapered seal portions on the radially outer side of the sleeve 11 only by attaching the ring seal member 19 having a simple configuration.

(4)
In the hydrodynamic bearing device 20 of the present embodiment, as shown in FIG. 3, as described above, the ring seal member 19 attached to provide a plurality of tapered seal portions on the radially outer side of the sleeve 11 is substantially horizontal. A bent hole 19a for communicating the second taper seal portion 22 disposed on the inner diameter side with the external space is provided in a part of the bent portion having a substantially L-shaped cross section projecting to the outside.

  Here, in the configuration in which the bent portion of the substantially L-shaped cross section is fixed in a state of being in contact with the outer peripheral surface of the sleeve 11, as shown in FIG. 2 and the like, the outer peripheral surface of the sleeve 11 and the inner peripheral surface of the ring seal member 19 are used. The 2nd taper seal part 22 formed in the clearance gap between surfaces will be in the state interrupted | blocked from external space. In this state, when axial vibration or impact is applied to the hydrodynamic bearing device 20, the gap between the rotor hub 15 and the upper surface of the ring seal member 19 and the upper surface of the sleeve 11 is closed. The two taper seal portion 22 becomes a sealed space. In the second taper seal portion 22 thus formed as a sealed space, negative pressure may be generated, and bubbles may be generated in the lubricating fluid 26 or the interface of the lubricating fluid 26 may become unstable.

  Thereby, even when an impact or the like in the axial direction is applied to the hydrodynamic bearing device 20 by communicating the second taper seal portion 22 with the external space via the bench hole 19a, the second taper seal portion 22 is The containing space is not sealed. As a result, the interface at the second taper seal portion 22 can be stabilized, and leakage of the lubricating fluid 26 from the second taper seal portion 22 can be prevented.

(5)
As shown in FIG. 2 and the like, the hydrodynamic bearing device 20 according to the present embodiment includes a radial bearing portion formed in a gap between the sleeve 11 and the shaft 12, and a first Between the 2nd taper seal parts 21 and 22, it has the fluid reservoir part 23 formed in the clearance gap between the opposing surfaces of the rotor hub 15 and the sleeve 11. FIG.

  Thereby, in addition to the plurality of tapered seal portions provided on the outer side in the radial direction of the sleeve 11, a space for storing the lubricating fluid 26 is provided in the gap between the opposed surfaces of the sleeve 11 and the rotor hub 15. The amount of the lubricating fluid 26 stored in the hydrodynamic bearing device 20 can be greatly increased. As a result, even when the lubricating fluid 26 held in the gap gradually decreases due to evaporation, leakage, or the like, the lubricating fluid 26 can be continuously supplied to the radial thrust bearing portion for a longer period than before. . Therefore, the life of the hydrodynamic bearing device 20 can be extended more effectively.

(6)
In the hydrodynamic bearing device 20 of the present embodiment, as shown in FIG. 2, the radial dynamic pressure generating groove 11c formed on either the inner peripheral surface of the sleeve 11 or the outer peripheral surface of the shaft 12 is asymmetric with respect to the axial direction. Is formed.

  Thereby, the force which moves to the desired direction with respect to the lubricating fluid 26 with which it filled in the micro clearance gap formed in the hydrodynamic bearing apparatus 20 can be provided, and it can circulate within the circulation path containing the communicating hole 11b. . As a result, even when air bubbles are mixed in the lubricating fluid 26 when an impact is applied to the hydrodynamic bearing device 20, the lubricating fluid 26 is circulated efficiently, so that the air bubbles are effectively transferred to the external space. And can be discharged. Therefore, leakage of the lubricating fluid 26 due to the mixing of bubbles into the lubricating fluid 26 can be prevented.

(7)
As shown in FIG. 1, the spindle motor 10 of this embodiment is equipped with the above-described hydrodynamic bearing device 20.

  As a result, the hydrodynamic bearing device 20 has a long life and a spindle having the same effect as described above that the hydrodynamic bearing device 20 having excellent angular rigidity can be obtained by sufficiently securing the radial bearing portion. The motor 10 can be obtained.

(Embodiment 2)
A spindle motor 310 equipped with a hydrodynamic bearing device 320 according to another embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIGS. 13 and 14, the hydrodynamic bearing device 320 mounted on the spindle motor 310 of the present embodiment forms the first and second tapered seal portions 21 and 22 on the radially outer side of the sleeve 11. The ring seal member 319 provided is different from the hydrodynamic bearing device 20 of the first embodiment in that the ring seal member 319 is attached not to the outer peripheral surface side of the sleeve 11 but to the drooping portion 315a side of the rotor hub (hub) 315. .

  That is, the hydrodynamic bearing device 320 of this embodiment includes a ring seal member 319 for forming a plurality of tapered seal portions on the radially outer side of the sleeve 11, similarly to the hydrodynamic bearing device 20 of the first embodiment. .

  As shown in FIG. 14, the ring seal member 319 is a substantially annular member having a substantially L-shaped cross section, and a gap between the outer peripheral surface and the inner peripheral surface of the hanging portion 315 a of the rotor hub 315 is provided in the gap. A first taper seal portion 21 is formed. On the other hand, a second taper seal portion 22 is formed in the gap between the inner peripheral surface of the ring seal member 319 and the outer peripheral surface of the sleeve 11. Furthermore, the ring seal member 319 has a bench hole 19a formed in a bottom portion extending outward in the radial direction.

  As shown in FIG. 14, the bench hole 319a is a substantially half-moon shaped opening (see FIG. 15) formed in the vicinity of a bent portion of a substantially L-shaped cross section extending substantially perpendicular to the axial direction. 1 The taper seal part 21 and external space are made to communicate. As shown in FIG. 15, one bench hole 319a may be provided along the circumferential direction, or a plurality of bench holes 319a may be provided. The bench hole 319a may be provided on the bottom surface side (bent portion) of the substantially L-shaped cross section, or may be provided on the side surface side substantially along the axial direction. It is preferable to arrange the bench hole 319a as far away from the communication hole 11b as possible. For example, as shown in FIG. 15, the position of the communication hole 11 b and the position of the bench hole 319 a are provided at opposite positions around the shaft 12. This is because, when an impact or vibration is applied, the lubricating fluid 26 may be pushed out through the communication hole 11 b, and the pushed lubricating fluid is the liquid level of the first taper seal portion 21 or the second taper seal portion 22. This is because it is possible to change the height and leak from the bench hole 319a. However, the size of the ring seal member 319 is usually determined so as not to leak from the bench hole 319a even if such a situation occurs.

  Further, the first and second taper seal portions 21 and 22 respectively formed on the inner and outer peripheral surfaces in the radial direction of the ring seal member 319 are disposed along an oblique direction with respect to the axial direction as shown in FIG. Has been. More specifically, the first and second tapered seal portions 21 and 22 are formed along a direction in which the diameter increases toward the rotor hub 315 side in the axial direction. Specifically, for example, the opposing surfaces of the ring seal member 319 and the sleeve 11 forming the first and second tapered seal portions 21 and 22 and the drooping portion 315a of the rotor hub 315 have a diameter toward the rotor hub 315 side in the axial direction. What is necessary is just to form diagonally so that may become large.

  Thereby, even when the centrifugal force generated with the rotation of the rotation side member (the rotor hub 315, etc.) is applied to the lubricating fluid 26 existing near the interface between the first and second taper seal portions 21, 22, Since the first and second tapered seal portions 21 and 22 are formed obliquely, the lubricating fluid 26 can be moved in a direction away from the interface. Therefore, it is possible to effectively avoid the lubricating fluid 26 from leaking from the vicinity of the interface between the first and second taper seal portions 21 and 22 during the rotation of the rotor hub 315 and the like.

  In the present embodiment, similarly to the first embodiment, a plurality of tapered seal portions (first and second) are provided on the radially outer side of the sleeve 11 using the ring seal member 319 fixed to the inner peripheral surface side of the rotor hub 315. Tapered seal portions 21 and 22) are provided. For this reason, the storage volume of the lubricating fluid 26 can be increased as compared with a conventional hydrodynamic bearing device having only one substantially annular tapered seal portion. In addition, the surface tension acting on the lubricating fluid 26 can be increased by having a plurality of tapered seal portions. Therefore, the lubricant fluid 26 can be prevented from being reduced due to evaporation, leakage to the outside, or the like by storing more lubricant fluid 26 than before while holding the lubricant fluid 26 firmly in the taper seal portion. .

  Further, by providing the plurality of taper seal portions on the radially outer side than the sleeve 11, the radial bearing portion formed in the gap between the sleeve 11 and the shaft 12 can be made long.

  As a result, a sufficient amount of the lubricating fluid 26 is firmly held in the gap including the bearing portion, thereby extending the life of the hydrodynamic bearing device 320 and ensuring sufficient length of the radial bearing portion. The hydrodynamic bearing device 320 having excellent rigidity can be obtained.

  Further, in the hydrodynamic bearing device 320 of the present embodiment, the ring seal member 319 is attached to the inner peripheral surface side of the rotor hub 315, so the ring seal member 319 also rotates together with the rotor hub 315. For this reason, the interface of the second taper seal part 22 on the inner peripheral surface side of the ring seal member 319 sandwiched between the rotation side member and the fixed side member is more than the interface of the first taper seal part 21 on the outer peripheral surface side. It will be in the state which is easy to fluctuate. Therefore, compared to the configuration in which the ring seal member 319 is fixed to the outer peripheral surface side of the sleeve 11, the interface that is likely to change moves from the outer peripheral surface side to the inner peripheral surface side of the ring seal member 319. The centrifugal force applied to the surrounding lubricating fluid 26 can be reduced, and leakage of the lubricating fluid 26 can be prevented.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

(A)
In the above-described embodiment, an example in which the sleeve 11 is formed as a single metal member has been described. However, the present invention is not limited to this.

  For example, as shown in FIGS. 6 (a) and 6 (b), 7 (a) and 7 (b), there is a sleeve 61 composed of two parts, an inner sleeve 61a and an outer sleeve 61b. Also good. The inner sleeve 61a may be one whose surface is sealed or one that is not sealed.

  In this case, as shown in FIG. 7B, the thrust flange 13 is provided with the outer sleeve 61b so that only the inner sleeve 61a is not loaded when the thrust flange 13 of the shaft 12 moves in the axial direction. It is preferable that the structure be in contact with the step portion 61ba.

(B)
In the above embodiment, the so-called flange-type hydrodynamic bearing device 20 in which the thrust flange 13 is attached to the shaft 12 has been described as an example. However, the present invention is not limited to this.

  For example, as shown in FIG. 8, a so-called flangeless type hydrodynamic bearing device 70 having no flange portion with respect to the shaft 72 may be used. In this case, it is possible to avoid the shaft 72 from coming out of the bearing hole 71 a of the sleeve 71 by providing the retaining member 73 in which the communication hole 73 a is formed.

(C)
In the embodiment described above, the configuration in which the gap between the opposed surfaces of the rotor hub 15 and the sleeve 11 is substantially uniform has been described as an example. However, the present invention is not limited to this.

  For example, as shown in FIG. 9, a configuration may be adopted in which a gap corresponding to the fluid reservoir 83 formed between the opposed surfaces of the rotor hub (hub) 85 and the sleeve 81 becomes wider radially outward. . In this case, since the suction force toward the radially inner side can be applied to the lubricating fluid by the capillary force, the lubricating fluid is prevented from being blown radially outward by the centrifugal force applied during the rotation. can do.

(D)
In the embodiment described above, the configuration in which the gap between the facing surfaces is used as a fluid reservoir without forming a dynamic pressure generating groove on any of the facing surfaces of the rotor hub 15 and the sleeve 11 has been described as an example. However, the present invention is not limited to this.

  For example, as shown in FIG. 10, a spiral (spiral) groove 91 a may be formed on one surface of the facing surface, for example, the upper surface of the sleeve 91. In this case, since the gap between the facing surfaces of the sleeve 91 and the rotor hub 15 is larger than the gap constituting the bearing portion, there is no dynamic pressure and the pressure on the radially inner side is set against the radially outer side. By increasing the height, the bubbles mixed in the lubricating fluid 26 can be smoothly discharged from the release portions (first and second interfaces) on the radially outer side.

  The spiral groove is not limited to the sleeve side, and may be formed on the rotor hub side facing it.

(E)
In the embodiment described above, the configuration in which the gap between the facing surfaces is used as a fluid reservoir without forming a dynamic pressure generating groove on any of the facing surfaces of the rotor hub 15 and the sleeve 11 has been described as an example. However, the present invention is not limited to this.

  For example, a thrust dynamic pressure generating groove may be formed on at least one of the opposing surfaces of the rotor hub and the sleeve. Even in this case, the lubricating fluid supplied to the bearing portion can be sufficiently stored by the configuration in which the plurality of tapered seal portions are arranged in the radial direction.

(F)
In the above-described embodiment, a so-called shaft rotation type hydrodynamic bearing device in which the shaft 12 is a rotation-side member has been described as an example. However, the present invention is not limited to this.

  For example, as shown in FIG. 12, the configuration of the present invention can be applied to a spindle motor 210 on which a fixed shaft type hydrodynamic bearing device 220 having a shaft 212 as a fixed member is mounted. Even in this case, the same effect as that of the above embodiment can be obtained by forming the tapered seal portions on both the outer and inner peripheral sides of the ring seal member 219 attached to the radially outer side of the sleeve 211.

(G)
In the above embodiment, an example in which two substantially circular tapered seal portions 21 and 22 are provided in the radial direction of the hydrodynamic bearing device 20 has been described. However, the present invention is not limited to this.

  For example, a configuration in which three or more substantially circular tapered seal portions in the radial direction are provided may be employed. Even in this case, since a larger amount of lubricating fluid can be held in the taper seal portion than usual, the length of the radial bearing portion is ensured while satisfying the demand for thinning, and the life of the hydrodynamic bearing device is extended. be able to.

(H)
In the above-described embodiment, an example has been described in which the asymmetric groove for applying the circulation force for circulating the lubricating fluid 26 filled in the gap in the hydrodynamic bearing device 20 is formed as the radial dynamic pressure generating groove 11c. However, the present invention is not limited to this.

  For example, only the thrust dynamic pressure generating groove may be an asymmetric groove, or both the radial and thrust dynamic pressure generating grooves may be asymmetric grooves.

(I)
In the above-described embodiment, an example in which the hydrodynamic bearing device 20 according to the present invention is mounted on the spindle motor 10 has been described. However, the present invention is not limited to this.

  For example, as shown in FIG. 11, a spindle motor 110 (fluid) mounted on a magnetic recording / reproducing apparatus (recording / reproducing apparatus) 150 having a recording head (recording / reproducing head unit) 152 that performs recording / reproducing on a recording / reproducing disk 151. The present invention can naturally be applied to the bearing device 120).

  Further, the recording / reproducing apparatus is not limited to the magnetic recording / reproducing apparatus, and can be mounted on other recording / reproducing apparatuses such as an optical disk.

(J)
In the embodiment described above, an example in which the fluid reservoir 23 is provided between the flat surfaces of the sleeve 11 and the rotor hubs 15 and 315 facing each other has been described. However, the present invention is not limited to this.

  For example, as shown in FIG. 16, a hydrodynamic bearing device 420 having a recess 415 b formed on a surface of the rotor hub (hub) 415 facing the sleeve 11 may be used.

  In this case, since the volume of the fluid reservoir 423 can be increased by the recess 415b formed on the rotor hub 415 side, the lubricating fluid 26 supplied to the bearing portion can be more sufficiently secured. Therefore, the life of the hydrodynamic bearing device 420 can be extended.

  As shown in FIG. 16, it is important that the portion of the rotor hub 415 facing the communication hole 11b has a small gap and the recess is provided from the outside in the radial direction. Thereby, the lubricating fluid 26 flowing out from the communication hole 11b can be reliably circulated in the direction of the bearing portion.

(K)
In the embodiment described above, an example in which the fluid reservoir 23 is provided between the flat surfaces of the sleeve 11 and the rotor hubs 15 and 315 facing each other has been described. However, the present invention is not limited to this.

  For example, as shown in FIG. 17, by providing a sleeve 511 having a portion (concave portion 515b) having a different axial height in the radial direction, a fluid reservoir 523 is formed between the facing surfaces of the sleeve 511 and the rotor hub 315. The structure like the hydrodynamic bearing device 520 may be used.

  As shown in FIG. 17, it is important that the recesses 515b formed in a part of the sleeve 511 have a very small gap between the opening of the communication hole 11b and the periphery of the bearing hole, similar to the fluid reservoir 523. It is. Thereby, the lubricating fluid 26 flowing out from the communication hole 11b can be effectively circulated in the direction of the bearing portion.

  The hydrodynamic bearing device of the present invention ensures a sufficient length of the radial bearing portion while satisfying the demand for thinning as a whole device, and also sufficiently stores the lubricating fluid supplied to the bearing portion and has a long service life. Therefore, the present invention can be widely applied to a hydrodynamic bearing device equipped with a hydrodynamic bearing device, for example, an HDD spindle motor or a high-density optical disc spindle motor.

A sectional view showing composition of a spindle motor carrying a fluid dynamic bearing device concerning one embodiment of the present invention. (A) is an expanded sectional view which shows the structure of a part of hydrodynamic bearing apparatus contained in the spindle motor of FIG. (B) is a top view which shows the asymmetrical groove pattern formed in the radial bearing part. The top view which shows the structure seen from the upper surface of the hydrodynamic bearing apparatus of FIG. Explanatory drawing which shows the procedure at the time of lubricating lubricating fluid in a vacuum chamber with respect to the hydrodynamic bearing apparatus of FIG. Explanatory drawing which shows the procedure at the time of filling the lubricating fluid after lubrication of FIG. (A), (b) is sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. (A), (b) is sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. Sectional drawing which shows the structure of the flangeless type hydrodynamic bearing apparatus which concerns on further another embodiment of this invention. Sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. The top view which shows the structure of the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. Sectional drawing which shows the structure of the magnetic recording / reproducing apparatus carrying the said hydrodynamic bearing apparatus. Sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on further another embodiment of this invention. Sectional drawing which shows the structure of the spindle motor carrying the hydrodynamic bearing apparatus which concerns on further another embodiment of this invention. FIG. 14 is an enlarged sectional view showing a configuration of a part of a hydrodynamic bearing device included in the spindle motor of FIG. 13. FIG. 15 is a cross-sectional view taken along line AA in FIG. 14. Sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on further another embodiment of this invention. Sectional drawing which shows the structure of the hydrodynamic bearing apparatus which concerns on further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Spindle motor 11 Sleeve 11a Bearing hole 11b Communication hole 11c Radial dynamic pressure generating groove (radial bearing part)
11e Stepped portion 12 Shaft 13 Thrust flange 13c Thrust dynamic pressure generating groove (thrust bearing portion)
14 Thrust plate 14c Thrust dynamic pressure generating groove (Thrust bearing)
15 Rotor hub (hub)
15a Hanging part 15aa Step 16 Rotor magnet 17 Stator 18 Base 18a Hollow cylindrical part 18b Hole 19 Ring seal member 19a Bench hole 20 Hydrodynamic bearing device 21 First taper seal part (taper seal part)
22 Second taper seal (taper seal)
23 Fluid reservoir portion 26 Lubricating fluid 50 Vacuum chamber 51 Lubricator 61 Sleeve 61a Inner sleeve 61b Outer sleeve 61ba Stepped portion 70 Fluid bearing device 71 Sleeve 71a Bearing hole 72 Shaft 73 Retaining member 73a Communication hole 81 Sleeve 83 Fluid reservoir portion 85 Rotor hub (Hub)
91 Sleeve 91a Groove 95 Rotor hub (hub)
110 Spindle motor 120 Fluid bearing device 150 Magnetic recording / reproducing apparatus (recording / reproducing apparatus)
151 Recording / Reproducing Disc 152 Recording Head (Recording / Reproducing Head)
210 Spindle motor 211 Sleeve 212 Shaft 219 Ring seal member 220 Fluid bearing device 310 Spindle motor 315 Rotor hub (hub)
315a Hanging part 319 Ring seal member 319a Bench hole 320 Hydrodynamic bearing device 415 Rotor hub (hub)
415a Suspended portion 415b Recess 420 Fluid bearing device 423 Fluid reservoir 511 Sleeve 515b Recess 520 Fluid bearing device 523 Fluid reservoir

Claims (18)

The axis,
A sleeve having a bearing hole in which the shaft is rotatably loaded via a lubricating fluid;
A hub attached to the rotating body rotating around the shaft so as to cover the open end side of the bearing hole in the sleeve;
A plurality of substantially annular taper seal portions that are disposed between a part of the hub and the sleeve on a radially outer side of the sleeve and hold the lubricating fluid;
A hydrodynamic bearing device. A ring-shaped ring seal member attached to the outer peripheral surface of the sleeve, wherein the plurality of taper seal portions are respectively formed on an inner peripheral side and an outer peripheral side;
The hydrodynamic bearing device according to claim 1. The ring seal member is
Forming a first taper seal portion between a substantially annular outer peripheral surface and a drooping portion extending substantially perpendicularly from the surface of the hub facing the sleeve toward the sleeve;
Forming a second taper seal portion between the substantially annular inner peripheral surface and the outer peripheral surface of the sleeve;
The hydrodynamic bearing device according to claim 2. The ring seal member has a substantially L-shaped cross-sectional shape along the radial direction of the substantially annular member.
The hydrodynamic bearing device according to claim 2. The ring seal member has a bench hole for communicating the taper seal portion with the outside air,
The hydrodynamic bearing device according to any one of claims 2 to 4. It is attached to the inner peripheral surface of the hub, and further comprises a substantially annular ring seal member in which the plurality of tapered seal portions are formed on the inner peripheral side and the outer peripheral side, respectively.
The hydrodynamic bearing device according to claim 1. The ring seal member is
Forming a first taper seal portion between a substantially annular outer peripheral surface and a drooping portion extending substantially perpendicularly from the surface of the hub facing the sleeve toward the sleeve;
Forming a second taper seal portion between the substantially annular inner peripheral surface and the outer peripheral surface of the sleeve;
The hydrodynamic bearing device according to claim 6. The ring seal member has a substantially L-shaped cross-sectional shape along the radial direction of the substantially annular member.
The hydrodynamic bearing device according to claim 6 or 7. The ring seal member has a bench hole for communicating the taper seal portion with the outside air,
The hydrodynamic bearing device according to any one of claims 6 to 8. The plurality of tapered seal portions are arranged along a direction in which the diameter increases toward the hub side in the axial direction.
The hydrodynamic bearing device according to any one of claims 1 to 9. A fluid reservoir formed in a gap between the hub and the sleeve;
The hydrodynamic bearing device according to claim 1. The hub has a recess that enlarges a space used as the fluid reservoir on a surface facing the sleeve.
The hydrodynamic bearing device according to claim 11. The sleeve has a recess having a different axial height in the radial direction as the fluid reservoir.
The hydrodynamic bearing device according to claim 11. A radial bearing portion and a thrust bearing portion;
At least one of the radial bearing portion and the thrust bearing portion has an asymmetric groove that imparts a circulation force to the lubricating fluid.
The hydrodynamic bearing device according to claim 1. A spiral groove formed on any one of the opposed surfaces of the hub and the sleeve;
The hydrodynamic bearing device according to claim 1. The gap between the opposite surfaces of the hub and the sleeve increases toward the radially outer side.
The hydrodynamic bearing device according to any one of claims 1 to 15.   A spindle motor comprising the hydrodynamic bearing device according to any one of claims 1 to 16. A recording / reproducing apparatus comprising the spindle motor according to claim 17.

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