JP2008064302A - Hydrodynamic bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the lowering of supporting force of a hydrodynamic bearing device in the thrusting direction by improving the wear resistance of a member facing a thrust bearing gap. <P>SOLUTION: The hydrodynamic bearing device comprises a housing 9 (a fixed-side member) injection-molded of a resin as an insert component for a thrust member 13 formed of a porous material, the thrust member 13 facing the thrust bearing gap T<SB>S</SB>. Thus, lubricating oil is gradually supplied from a surface hole opening portion of the thrust member 13 into the thrust bearing gap T<SB>S</SB>to improve lubricating performance. This prevents the wear of an upper end face 9a of the housing 9 to maintain the accuracy of the gap width of the thrust bearing gap T<SB>S</SB>, preventing the lowering of the supporting force in the thrusting direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydrodynamic bearing device that rotatably supports a shaft portion by a hydrodynamic action of a fluid film formed in a bearing gap.

  Due to its high rotational accuracy and quietness, the hydrodynamic bearing device is an information device, for example, a magnetic disk drive device such as HDD, an optical disk drive device such as CD-ROM, CD-R / RW, DVD-ROM / RAM, MD, Suitable for spindle motors such as magneto-optical disk drive devices such as MOs, small motors such as fan motors used for laser beam printer (LBP) polygon scanner motors, projector color wheels, cooling fans for electrical equipment, etc. Can be used.

  For example, a hydrodynamic bearing device disclosed in Patent Literature 1 holds a shaft portion, a disk hub fixed to the shaft portion, a bearing sleeve having the shaft portion inserted into the inner periphery, and the bearing sleeve on the inner periphery. And a resin housing. A radial bearing gap is formed between the outer peripheral surface of the shaft portion and the inner peripheral surface of the bearing sleeve, and a thrust bearing gap is formed between the end surface of the housing and the end surface of the disk hub. When the shaft portion rotates, a dynamic pressure action is generated in the lubricating fluid in the thrust bearing gap and the radial bearing gap.

JP 2005-337341 A

  Thus, when the housing is formed of a resin material, the material cost can be reduced as compared with the case where the housing is formed of a metal material. However, since the resin material is inferior to the metal material in terms of wear resistance, the housing end face and the disk facing each other through the thrust bearing gap at the time of low speed rotation such as starting and stopping of the bearing device in which the dynamic pressure action is not sufficiently exhibited. There is a risk that the end surface of the resin housing will wear due to contact sliding with the end surface of the hub. When the housing end face is worn, the accuracy of the gap width of the thrust bearing gap is lowered, and the supporting force in the thrust direction is lowered.

  The subject of this invention is preventing the fall of the supporting force of the thrust direction of a hydrodynamic bearing apparatus by improving the abrasion resistance of the member which faces a thrust bearing clearance gap.

  In order to solve the above problems, the present invention is directed to a fixed member, a rotating member, a thrust bearing gap formed between the fixed member and the rotating member, and a lubricating fluid in the thrust bearing gap. In the hydrodynamic bearing device including a thrust dynamic pressure generating unit that generates a dynamic pressure action on the shaft, either one of the fixed side member and the rotation side member includes a thrust member that faces the thrust bearing gap. It is a resin molded product.

  As described above, in the present invention, any one of the members facing each other through the thrust bearing gap is a resin molded product provided with a thrust member facing the thrust bearing gap. Accordingly, for example, when the thrust member is formed of a porous material, the lubricating fluid impregnated in the porous material is sequentially supplied to the thrust bearing gap, so that the lubricity between the members facing each other through the thrust bearing gap is improved. . Therefore, since the wear of the member facing the thrust bearing gap can be suppressed, the accuracy of the gap width of the thrust bearing gap is maintained, and the reduction of the supporting force in the thrust direction can be avoided. Alternatively, when the thrust member is formed of a hard metal material, the hardness of the portion facing the thrust bearing gap is increased, and the wear resistance of this portion can be improved.

  When the thrust bearing gap has a gap width of zero when the rotating side member is stationary, the opposing members are in contact with each other through the thrust bearing gap each time the bearing device is started and stopped. In such a bearing device, the effect of improving the wear resistance of the portion facing the thrust bearing gap is particularly effective.

  Further, when the thrust dynamic pressure generating portion is formed on the thrust member, if this portion is worn, the supporting force in the thrust direction is greatly reduced. Therefore, it is effective to suppress wear of the thrust dynamic pressure generating portion by the effect of improving the lubricity or hardness as described above.

  This resin molded product can be molded by inserting a thrust member, for example. At this time, since the resin molded portion contracts in the diameter-reducing direction due to molding shrinkage when the resin is solidified, the resin molded portion may be displaced with respect to the thrust member, and the fixed portions may be peeled off. Therefore, if the outer peripheral surface of the thrust member is held by the resin, even if the resin molded product contracts in the diameter reducing direction, it is possible to prevent deviation from the thrust member.

  As described above, according to the present invention, it is possible to prevent a reduction in the supporting force in the thrust direction of the hydrodynamic bearing device by improving the wear resistance of the member facing the thrust bearing gap.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.

  FIG. 1 conceptually shows a configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device 1 according to a first embodiment of the present invention. The spindle motor is used in a disk drive device such as an HDD, and is opposed to the dynamic pressure bearing device 1 that rotatably supports the shaft portion 2 and the disk hub 10 through a gap in the radial direction, for example. A stator coil 4, a rotor magnet 5, and a bracket 6 are provided. The stator coil 4 is attached to the bracket 6, and the rotor magnet 5 is fixed to the disk hub 10. The hydrodynamic bearing device 1 is fixed to the inner periphery of the bracket 6. Although not shown, the disk hub 10 holds one or more disks as information recording media. In the spindle motor configured as described above, when the stator coil 4 is energized, the rotor magnet 5 is rotated by an exciting force generated between the stator coil 4 and the rotor magnet 5, and accordingly, the disk hub 10 and the disk are rotated. The disk held by the hub 10 rotates integrally with the shaft portion 2.

  FIG. 2 shows the hydrodynamic bearing device 1. The hydrodynamic bearing device 1 includes a shaft portion 2, a disk hub 10 as a rotating member fixed to the outer peripheral surface of the shaft portion 2, a bearing sleeve 8 having the shaft portion 2 inserted on the inner periphery, and a bearing sleeve. 8 is provided with a housing 9 as a fixed-side member that is held on the inner periphery and opened in one axial direction. For convenience of explanation, the side where the housing 9 is opened will be described as an upper side, and the side where the housing 9 is closed will be described as a lower side.

A radial bearing gap is formed between the inner peripheral surface 8 a of the bearing sleeve 8 and the outer peripheral surface 2 a of the shaft portion 2, and between the end surface 10 a 1 of the disk hub 10 and the upper end surface 9 a of the housing 9, thrust bearing gap T _S is formed. The space filled with the lubricating oil inside the bearing is opened to the atmosphere on one end side of the radial bearing gap and sealed on the other end side. Thrust bearing gap T _S is provided to the air open side of the radial bearing gap, one end of the radial bearing gap is in communication with the inner diameter end of the thrust bearing gap T _S. Time of stopping the motor, i.e. at rest on the shaft portion 2 and the disk hub 10, and the disk hub 10 and the housing 9 are in contact by gravity, the gap width of the thrust bearing gap T _S is zero. For example, when the hydrodynamic bearing device 1 is used upside down with respect to FIG. 2, the disk hub 10 does not contact the housing 9 even when the motor is stopped. In this case, by utilizing a magnetic force or the like, forced into contact with the disk hub 10 and the housing 9, the gap width of the thrust bearing gap T _S during the motor stop can be zero.

  The bearing sleeve 8 is formed, for example, in a cylindrical shape with a porous material such as a sintered metal containing copper as a main component, and is press-fitted into the inner peripheral surface 9c of the housing 9 with bonding, press-fitting, and interposing an adhesive ( Hereinafter, it is referred to as press-fit adhesion) or is fixed by appropriate means such as welding. The bearing sleeve 8 can be formed of other metal materials, resin materials, ceramics, or the like.

  A region where a plurality of dynamic pressure grooves are arranged as a radial dynamic pressure generating portion is formed on the entire inner surface or a partial cylindrical region of the inner peripheral surface 8a of the bearing sleeve 8. In this embodiment, for example, as shown in FIG. 3, two regions where a plurality of dynamic pressure grooves 8a1 and 8a2 are arranged in a herringbone shape are formed apart from each other in the axial direction. The dynamic pressure grooves 8a1 and 8a2 are not necessarily provided separately in the axial direction, and may be formed continuously in the axial direction. Alternatively, only one of the dynamic pressure grooves 8a1 and 8a2 may be formed.

The housing 9 is a resin molded product obtained by injection molding using the thrust member 13 as an insert part. In this embodiment, the housing 9 is formed in a cup shape with a bottomed cylinder. The thrust member 13 is formed of a porous material in the present embodiment, and is formed of, for example, a sintered metal containing copper as a main component. The upper end surface 13a of the thrust member 13 is exposed to the upper end surface 9a of the housing 9, and as a dynamic pressure generating portion, for example, a pump-in type spiral shape with respect to the rotation direction A of the shaft portion 2 as shown in FIG. A plurality of dynamic pressure grooves 13a1 arranged in the same manner are formed. When the shaft portion 2 rotates, the animal groove 13a1 region opposed to each other with the end surface 10a1 of the thrust bearing gap T _S of the disk hub 10 (see FIG. 2 an enlarged view). An annular tapered surface 9b1 that gradually increases in diameter upward is formed on the upper portion of the outer peripheral surface 9b of the housing 9, and a cylindrical surface 9b2 is formed on the lower portion of the outer peripheral surface 9b. The cylindrical surface 9b2 is fixed to the inner peripheral surface of the bracket 6 by means such as adhesion, press-fitting, and press-fitting adhesion.

  The resin molding part 14 of the housing 9 is made of, for example, a crystalline resin such as liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenyl sulfone (PPSU), polyether sulfone (PES). ), A resin composition having an amorphous resin such as polyetherimide (PEI) as a base resin. Examples of fillers that can be added to the resin include fibrous fillers such as carbon fibers and glass fibers, whisker-like fillers such as potassium titanate, scaly fillers such as mica, carbon black, graphite, and carbon nano Examples thereof include conductive fillers such as materials and various metal powders. These fillers are blended in an appropriate amount in the base resin depending on the purpose, such as reinforcement of the resin molded portion 14 or imparting conductivity. The linear expansion coefficient of the resin material is desirably as close as possible to the linear expansion coefficient of the thrust member 13 by appropriately blending a filler. This is to suppress a difference in thermal expansion between the resin molded portion 14 and the thrust member 13 at a high temperature.

  By the way, the resin molding part 14 is contracted in the diameter reducing direction by molding contraction at the time of solidification. For this reason, there exists a possibility that the thrust member 13 and the resin molding part 14 may shift | deviate, and these adhering parts may peel. In the present invention, as shown in FIG. 2, since the outer peripheral surface 13b of the thrust member 13 is held by the resin molded portion 14, the thrust member 13 is formed when the outer peripheral surface of the resin molded portion 14 is reduced in diameter by molding shrinkage. And the resin molded portion 14 can be prevented from shifting. Further, in the present embodiment, the chamfer portions 13b1 and 13c1 formed on the upper end portions of the outer peripheral surface 13b and the inner peripheral surface 13c of the thrust member 13 restrict the removal of the thrust member 13 from the resin molded portion 14. Furthermore, when the resin molding part 14 enters the surface opening part of the thrust member 13 made of a porous material, an anchor effect is exhibited, and the thrust member 13 and the resin molding part 14 are firmly fixed.

  The shaft portion 2 is formed in a cylindrical shape with a metal material such as SUS steel. In addition, you may form a recessed part in the part to which the disk hub 10 is fixed among the outer peripheral surfaces 2a of the axial part 2. As shown in FIG. This recess can function as an adhesive reservoir, for example.

  The disk hub 10 is formed of, for example, a metal material, and is fixed to the shaft portion 2 by appropriate means such as adhesion, press-fitting, and press-fitting adhesion. The disk hub 10 includes a disk portion 10a that covers the opening side (upper side) of the housing 9, a cylindrical portion 10b that extends downward in the axial direction from the outer peripheral portion of the disk portion 10a, and a flange that protrudes outward from the cylindrical portion 10b. A disk mounting surface 10d formed at the upper ends of the portion 10c and the flange portion 10c. A disk (not shown) is fitted on the outer periphery of the disk portion 10a and placed on the disk mounting surface 10d. Then, the disc is held on the disc hub 10 by appropriate holding means (clamper or the like) not shown. The material for forming the disk hub 10 is not limited to metal, and for example, resin may be used. Further, the disc hub 10 and the shaft portion 2 may be formed separately as described above, or the shaft portion 2 may be formed integrally with the disc hub 10 by resin injection molding using the shaft portion 2 as an insert part. . Alternatively, the shaft portion 2 and the disc hub 10 may be integrally formed with the same kind of resin.

A retaining member 12 made of a metal, for example, a soft metal such as brass, is disposed on the inner periphery of the disk hub 10. In this embodiment, the retaining member 12 is formed in a ring shape having a substantially L-shaped cross section by, for example, press molding of a metal plate, and is attached to a step portion 10e provided on the inner periphery of the disc hub 10 by adhesion, welding, or the like. It is fixed by appropriate means. The retaining member 12 engages with the outer peripheral surface 9b of the housing 9, more specifically, the shoulder surface extending from the upper end of the tapered surface 9b1 to the outer diameter, thereby restricting the disc hub 10 and the shaft portion 2 from coming off. Between the inner peripheral surface 12a of the retaining member 12 and the tapered surface 9d provided on the outer peripheral surface 9b of the housing 9 facing this, an annular seal space S whose radial dimension is gradually reduced upward is formed. Form. The seal space S, as shown in the enlarged view of FIG. 2, during rotation of the shaft portion 2 and the disk hub 10 is in fluid outer diameter side and the communication of the thrust bearing gap T _S of the thrust bearing portion T1.

  As the lubricating oil filled in the hydrodynamic bearing device 1, various types of lubricating oil can be used, but the lubricating oil provided to the hydrodynamic bearing device for a disk drive device such as an HDD may be used at the time of use or In consideration of temperature changes during transportation, ester-based lubricating oils that are excellent in low evaporation rate and low viscosity, such as lubricating oils based on dioctyl sebacate (DOS), dioctyl azelate (DOZ), etc. are preferred. It can be used.

  In the dynamic pressure bearing device 1 having the above-described configuration, when the shaft portion 2 rotates, the lubricating oil in the radial bearing gap formed between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface 2a of the shaft portion 2 The groove 8a1, 8a2 is pushed into the axial center, and the pressure rises. In this manner, the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft portion 2 in a non-contact manner in the radial direction are configured by the dynamic pressure action of the lubricating oil generated by the dynamic pressure grooves 8a1 and 8a2. .

At the same time, the lubricating oil film pressure of which is formed in the thrust bearing gap T _S between the lower end surface 10a1 of the upper end surface 9a and the disk hub 10 of the housing 9, it is enhanced by the dynamic pressure effect of the dynamic pressure grooves 13a1. And the thrust bearing part T which non-contact-supports the axial part 2 and the disc hub 10 in a thrust direction is comprised by the pressure of these oil films.

Further, a porous thrust member 13 exposed from the upper end surface 9a of the housing 9, by lubricating oil to the thrust bearing gap T _S is supplied sequentially, housing 9 facing over the thrust bearing gap T _S and the disk hub 10 and the lubricity. Thus, it is possible to suppress the wear of the upper end surface 9a and dynamic pressure grooves formed in the surface of the housing 9, decrease in accuracy of the gap width of the thrust bearing gap T _S, the dynamic pressure due to wear of the dynamic pressure grooves It is possible to prevent a decrease in the action and maintain the bearing rigidity in the thrust direction. As in this embodiment, if the gap width of the thrust bearing gap T _S at the shaft portion 2 still is zero, starting the motor, and the end surface 10a1 of the upper end surface 9a and the disk hub 10 of the housing 9 every stop Since the sliding operation is performed, the effect of improving the lubricity as described above is effective. Therefore, the bearing device of the present invention can be particularly suitably used for a motor incorporated in a device that is frequently started and stopped, such as a personal computer and a portable music player.

By the way, when the thrust member 13 faces the thrust bearing gap T _S , the advantage that the lubricity is improved as described above can be obtained, while the lubricating oil whose pressure is increased by the dynamic pressure action is made of a porous material. The so-called dynamic pressure loss that escapes from the surface opening portion 13 to the inside occurs, and the dynamic pressure effect may not be sufficiently obtained. In the present invention, of the surface of the thrust member 13, a portion not Mensa the thrust bearing gap T _S, i.e. the outer circumferential surface 13b, the inner peripheral surface 13c, and the lower end surface covered with a resin, the surface openings of the part by sealing, since the discharge of oil from the surface opening of the portion not Mensa the thrust bearing gap T _S is suppressed, the oil is less likely to penetrate into the interior of the thrust member 13, to suppress the only dynamic depressurization Can do.

  Further, in the present embodiment, one or a plurality of, for example, three axial grooves 8 c arranged at equal intervals in the circumferential direction are formed on the outer peripheral surface of the bearing sleeve 8, and the inner bottom surface 9 d of the housing 9 is formed. Is formed with a radial groove 9d1 communicating with the axial groove 8c1. A gap (first space) formed between the upper end surface 8d of the bearing sleeve 8 and the lower end surface 10a1 of the disk portion 10a of the disk hub 10 by the axial groove 8c and the radial groove 9d1, and a radial bearing gap It is possible to communicate with a space (second space) in which the lower end of each of the two is opened. As a result, it is possible to prevent local negative pressure from being generated in the lubricating oil inside the bearing or to locally deteriorate the lubricating oil, so that it is possible to prevent a decrease in bearing performance associated therewith. Moreover, in this embodiment, as shown in FIG. 3, the dynamic pressure groove 8a1 has an asymmetric shape in the axial direction with respect to the axial center. As a result, when the shaft portion 2 rotates, the lubricating oil in the radial bearing gap is pushed downward, and the lubricating oil inside the bearing is circulated through the path of the second space → the radial groove 9d1 → the axial groove 8c1 → the first space. Then, it is again drawn into the radial bearing gap. Thus, by forcibly circulating the lubricating oil, the generation of negative pressure inside the bearing can be more effectively prevented.

  The embodiment of the present invention is not limited to the above. In the following description, portions having the same functions as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 5 shows a fluid dynamic bearing device 21 according to a second embodiment of the present invention. The dynamic pressure bearing device 21 includes a flange portion 2c that functions as a retaining member for the rotating member 3 at the lower end of the shaft portion 2, and a spiral (not shown) as a dynamic pressure generating portion on the lower end surface 8b of the bearing sleeve 8. A shaped dynamic pressure groove is formed. When the shaft portion 2 is rotated, the first thrust bearing portion T1 is formed between the upper end surface 9a of the housing 9 and the lower end surface 10a1 of the disk portion 10a of the disk hub 10 as in the above embodiment. The dynamic pressure groove on the lower end face 8b of the bearing sleeve 8 generates a dynamic pressure action on the lubricating oil in the thrust bearing gap formed between the lower end face 8b of the bearing sleeve 8 and the upper end face 2c1 of the flange portion 2c. Thus, the second thrust bearing portion T2 that supports the shaft portion 2 and the disk hub 10 in the thrust direction is formed. Thus, by providing the thrust bearing portions at two locations separated in the axial direction, bearing rigidity in the thrust direction, particularly moment rigidity is improved.

  FIG. 6 shows a fluid dynamic bearing device 31 according to a third embodiment of the present invention. In this embodiment, the bearing sleeve 8 and the thrust member 13 are in close contact with each other and are integrally formed. Thereby, compared with said embodiment which forms these separately, it can reduce the number of manufacturing processes. At this time, the dynamic pressure generating portion that generates the dynamic pressure action in the thrust bearing gap of the first thrust bearing portion T1 extends over the upper end surface 13a of the thrust member 13, the upper end surface 8d of the bearing sleeve 8, or both of them. Can be formed. Further, the bearing sleeve 8 and the thrust member 13 can be formed separately while maintaining the tight contact state.

  In the hydrodynamic bearing device 31, radial grooves are provided in the lower end surface 8b of the bearing sleeve 8 and the lower end surface 13d of the thrust member 13, respectively, and the outer peripheral surface 8c of the bearing sleeve 8 and the outer peripheral surface 13b of the thrust member 13 are provided. Each is provided with an axial groove. These radial grooves and axial grooves allow the lower end of the radial bearing gap to communicate with the outer diameter end of the thrust bearing gap.

  In the above embodiment, the thrust member 13 is formed of a sintered metal. However, the present invention is not limited to this. For example, the thrust member 13 may be formed of a porous resin. The porous resin is formed, for example, by mixing a base resin with a water-soluble compound as a pore-forming material and then molding the product, washing the molded product with water, and extracting the pore-forming material. As the water-soluble compound, for example, an organic alkali metal salt such as sodium benzoate can be used. In addition, as the base resin, a resin having excellent slidability and a glass transition point higher than the injection molding temperature of the resin molding portion 14 can be used. Moreover, you may add appropriate fillers, such as a reinforcing agent, to this porous resin.

Or the thrust member 13 can also be formed with a metal material like the hydrodynamic bearing apparatus 41 which concerns on 4th Embodiment of this invention shown in FIG. In this case, the thrust member 13 is formed by cutting such as stainless steel, and a thrust dynamic pressure generating portion is press-molded on the upper end surface 13a. Thus, by forming the thrust member 13 with a metal material, particularly a hard metal such as stainless steel, the hardness of the upper end surface 13a of the thrust member 13 facing the thrust bearing gap can be increased. Abrasion resistance is improved. Therefore, similar to the embodiments described above, decrease in accuracy of the gap width of the thrust bearing gap T _S, can prevent reduction in the dynamic pressure effect due to wear of the dynamic pressure grooves, it is possible to maintain the supporting force in the thrust direction . In addition, since the thrust dynamic pressure generating portion is press-molded on the thrust member 13 made of a metal material, there is no risk of forming defects due to sinking or sagging unlike when the resin molded portion is molded. The molding accuracy of the part can be increased. Moreover, according to the structure shown in FIG. 7, since the engaging part with the retaining member 12 of the housing 9 can be formed with the thrust member 13 made of a metal material, the durability of this part can be improved. it can.

In the above embodiments, among the opposing member via a thrust bearing gap T _S, it shows the case housing 9 is a resin molded article in which the thrust member 13 and the insert part, for example, shown in FIG. 8 As in the hydrodynamic bearing device 51 according to the fifth embodiment of the present invention, the housing 9 can be formed of a single material, and the disk hub 10 can be a resin molded product provided with a thrust member. At this time, the lower end surface 10a1 of the disk portion 10a of the disk hub 10 is formed by the thrust member 13, and the thrust member 13 faces the thrust bearing gap, whereby the wear resistance of the disk hub 10 can be improved. .

  Moreover, in the above embodiment, although the case where the housing 9 is formed by the injection molding of the resin which inserted the thrust member 13 is shown, not only this but the thrust member 13 and the resin molding part 14 are formed separately. After that, the housing 9 may be formed by fixing by an appropriate method such as adhesion, press-fitting, or press-fitting adhesion.

  In the above embodiment, the housing 9 formed separately and the bearing sleeve 8 are fixed by bonding or the like. However, the housing 9 may be injection molded using the bearing sleeve 8 as an insert part. According to this, since the assembly process of the housing 9 and the bearing sleeve 8 can be reduced, the process is simplified. In this case, the bearing sleeve 8 and the thrust member 13 are preferably formed of a material having a small difference in linear expansion coefficient, for example, the same kind of material. Alternatively, the housing 9 and the bearing sleeve 8 may be integrally formed of the same kind of resin material.

  In the above, the radial dynamic pressure generating portion and the thrust dynamic pressure generating portion are members made of a porous material such as the inner peripheral surface 8a of the bearing sleeve 8, the upper end surface 9a of the housing 9, and the lower end surface 8b of the bearing sleeve 8. However, the present invention is not limited to this, and is not limited to this. The surfaces facing each other through the bearing gaps, that is, the outer peripheral surface 2a of the shaft portion 2, the lower end surface 10a1 of the disk portion 10a of the disk hub 10, and the flange portion 2b. It can also be formed on the upper end surface 2b1.

  In addition, the shape of the dynamic pressure generating portion is not limited to the above, and for example, as a dynamic pressure generating portion of the radial bearing portion, a spiral dynamic pressure groove, a step bearing, a multi-arc bearing, or the like can be formed. Further, a herringbone-shaped dynamic pressure groove, a step bearing, a wave bearing, or the like can be formed as the dynamic pressure generating portion of the thrust bearing portion.

  In the above description, the lubricating oil is used as the lubricating fluid filled in the bearing. However, the present invention is not limited to this. For example, lubricating grease, magnetic fluid, or a gas such as air can be used.

  Further, the hydrodynamic bearing device of the present invention is not limited to the spindle motor used in the disk drive device such as the HDD as described above, but is used for information used under high-speed rotation, such as a spindle motor for driving a magneto-optical disk of an optical disk. It can also be suitably used as a fan motor for rotating shaft support in a small motor for equipment, a polygon scanner motor of a laser beam printer, or a cooling fan for electrical equipment.

It is sectional drawing of the spindle motor incorporating the dynamic pressure bearing apparatus. 1 is a cross-sectional view of a fluid dynamic bearing device 1. FIG. 3 is a cross-sectional view of a bearing sleeve 8. FIG. FIG. 6 is a top view of the housing 9. It is sectional drawing of the hydrodynamic bearing apparatus 21 which shows the 2nd Embodiment of this invention. It is sectional drawing of the hydrodynamic bearing apparatus 31 which shows 3rd Embodiment of this invention. It is sectional drawing of the hydrodynamic bearing apparatus 41 which shows 4th Embodiment of this invention. It is sectional drawing of the hydrodynamic bearing apparatus 51 which shows 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic pressure bearing apparatus 2 Shaft part 8 Bearing sleeve 9 Housing (member on the fixed side)
10 Disc hub (rotary member)
12 Stopping member 13 Thrust member 14 Resin molding part R1, R2 Radial bearing part T1, T2 Thrust bearing part T _S Thrust bearing gap S Seal space

Claims (7)

Thrust dynamic pressure generation that generates a dynamic pressure action on the lubricating fluid in the thrust bearing gap, and a thrust bearing gap formed between the fixed side member, the rotation side member, the fixed side member, and the rotation side member In the hydrodynamic bearing device provided with a portion,
One of the fixed-side member and the rotating-side member is a resin molded product provided with a thrust member facing the thrust bearing gap.   The hydrodynamic bearing device according to claim 1, wherein the thrust member is formed of a porous material.   The hydrodynamic bearing device according to claim 1, wherein the thrust member is formed of a metal material.   The hydrodynamic bearing device according to claim 1, wherein the thrust bearing gap has a gap width of 0 when the rotating member is stationary.   The hydrodynamic bearing device according to claim 1, wherein a thrust dynamic pressure generating portion is formed on the thrust member.   The hydrodynamic bearing device according to claim 1, wherein the resin molded product is formed by inserting the thrust member.   The hydrodynamic bearing device according to claim 6, wherein an outer peripheral surface of the thrust member is held by resin in the resin molded product.

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