WO2007111218A1 - 流体軸受装置 - Google Patents
流体軸受装置 Download PDFInfo
- Publication number
- WO2007111218A1 WO2007111218A1 PCT/JP2007/055859 JP2007055859W WO2007111218A1 WO 2007111218 A1 WO2007111218 A1 WO 2007111218A1 JP 2007055859 W JP2007055859 W JP 2007055859W WO 2007111218 A1 WO2007111218 A1 WO 2007111218A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- bearing
- dynamic pressure
- radial
- shaft member
- peripheral surface
- Prior art date
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C32/00—Bearings not otherwise provided for
- F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/10—Sliding-contact bearings for exclusively rotary movement for both radial and axial load
- F16C17/102—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure
- F16C17/107—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure with at least one surface for radial load and at least one surface for axial load
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/10—Sliding-contact bearings for exclusively rotary movement for both radial and axial load
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/26—Systems consisting of a plurality of sliding-contact bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/10—Construction relative to lubrication
- F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
- F16C33/106—Details of distribution or circulation inside the bearings, e.g. details of the bearing surfaces to affect flow or pressure of the liquid
- F16C33/107—Grooves for generating pressure
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
- H02K5/167—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings
- H02K5/1675—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings radially supporting the rotary shaft at only one end of the rotor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/08—Structural association with bearings
Definitions
- the present invention relates to a fluid dynamic bearing device.
- a hydrodynamic bearing device supports a shaft member rotatably with an oil film formed in a bearing gap.
- This hydrodynamic bearing device has features such as high-speed rotation, high rotation accuracy, and low noise.
- the fluid bearing device has been actively used for information devices, such as magnetic disk devices such as HDD and FDD, CD-ROM, CD. -R / RW, DVD—Spindle motors mounted on optical disk devices such as ROM / RAM, magneto-optical disk devices such as MD and MO, etc. Also mounted on personal computers (pc) to cool the heat source. It is widely used as a bearing for fan motors.
- both a radial bearing portion that supports a shaft member in the radial direction and a thrust bearing portion that supports the thrust direction are configured by dynamic pressure bearings.
- a radial bearing part in this type of fluid bearing device for example, as described in Japanese Patent Application Laid-Open No. 2003-239951 (Patent Document 1), an inner peripheral surface of a bearing sleeve and an outer peripheral surface of a shaft member opposed to the inner peripheral surface are used. It is known that a dynamic pressure groove as a dynamic pressure generating portion is formed on either one of them, and a radial bearing gap is formed between both surfaces.
- An information device incorporating the above-described hydrodynamic bearing device for example, a disk drive device such as an HDD, is required to mount a plurality of disks for the purpose of high capacity storage.
- the moment load acting on the bearing that rotatably supports the spindle shaft increases.
- a configuration in which a plurality of radial bearings are provided on the inner peripheral side of one bearing sleeve is widely adopted, including Patent Document 1 described above.
- each bearing sleeve has a different arrangement pattern and formation location of the dynamic pressure grooves provided on the inner peripheral surface in consideration of the rotation direction, but the shafts thereof are different.
- the directional dimensions are the same, and the difference in appearance is very small.
- Patent Document 4 As a hydrodynamic bearing device having this type of structure, for example, JP-A-2005-321089 As disclosed in Japanese Patent Publication (Patent Document 4), there is known a bearing sleeve provided with thrust bearing portions on both ends. A configuration in which the configurations of Patent Document 2 (or Patent Document 3) and Patent Document 4 described above are combined can be employed with the aim of further improving the moment rigidity.
- dynamic pressure generating means such as a dynamic pressure groove that generates fluid dynamic pressure in the thrust bearing gap is often provided on the end face of the sintered metal bearing sleeve in consideration of formability.
- each dynamic pressure groove needs to have a different tilt direction in consideration of the rotation direction. Therefore, the force that requires two types of bearing sleeves. These are difficult to discern visually, and are formed in substantially the same shape at the level, so the assembly direction and assembly position are likely to be erroneous. If the direction of assembly is incorrect, it may not function as a bearing device in the same way as described above. Therefore, special consideration is required for assembly, which increases the manufacturing cost of the bearing device.
- the rotational performance of the hydrodynamic bearing device is determined by the width accuracy of the bearing gap (for example, radial bearing gap). For this reason, efforts have been made to accurately form the outer peripheral surface of the shaft member forming the radial bearing gap and the inner peripheral surface of the bearing sleeve (bearing member). In many cases, the radial width of the radial bearing gap is uniformly formed over the entire length in the axial direction as described in, for example, JP-A-2004-132402 (Patent Document 5).
- a hydrodynamic bearing device incorporated in a spindle motor is required to improve not only the moment rigidity as described above but also the rotational accuracy.
- it is necessary to finish the inner peripheral surface of the bearing member that forms the radial bearing gap and the outer peripheral surface of the shaft member with higher accuracy but generally it is not necessary to finish the inner peripheral surface with high accuracy. It is more difficult than finishing the peripheral surface with high accuracy, and there is a limit to increasing machining accuracy by general machining.
- Patent Document 1 Japanese Patent Laid-Open No. 2003-239951
- Patent Document 2 JP-A-11-1269475
- Patent Document 3 Japanese Patent No. 3602707
- Patent Document 4 Japanese Patent Laid-Open No. 2005-321089
- Patent Document 5 Japanese Unexamined Patent Application Publication No. 2004-132402 Disclosure of the invention
- the present invention has been made in view of the above problems.
- the first problem is that the moment rigidity is excellent, the bearing sleeve is easy to manufacture, and the work efficiency of assembly and component management is improved.
- An object of the present invention is to provide a hydrodynamic bearing device which can be improved.
- a second object of the present invention is to provide a hydrodynamic bearing device capable of exhibiting high moment rigidity while avoiding as much as possible a decrease in bearing performance due to assembly accuracy.
- a third object of the present invention is to provide a hydrodynamic bearing device that improves the width accuracy of the radial bearing gap and is excellent in bearing performance including moment rigidity at low cost. Means for solving the problem
- a bearing sleeve having a radial bearing surface, a shaft member inserted into the inner periphery of the bearing sleeve, a radial bearing surface of the bearing sleeve, and a shaft member
- a hydrodynamic bearing device including a radial bearing portion that supports a shaft member in a radial non-contact manner by a dynamic pressure action of a fluid generated in a radial bearing gap with an outer peripheral surface, a plurality of bearing sleeves are arranged in the axial direction.
- the hydrodynamic bearing device is characterized in that the bearing sleeves are formed to have different axial lengths.
- the bearing sleeves are arranged at a plurality of positions in the axial direction, the span between the radial bearing portions can be increased to increase the load capacity against the moment load, and the manufacture of the bearing sleeve Can be made easier.
- the axial lengths of multiple bearing sleeves arranged in the axial direction are different from each other, the difference in appearance is clarified, and it is possible to reliably prevent incorrect assembly. Simplification can be achieved.
- the radial bearing surface of one bearing sleeve is the end on the side away from the other bearing sleeve. It is customary to be provided on the inner periphery of the part. However, in this case, in particular, it becomes difficult to secure a coaxial between both ends of the bearing sleeve on the side where the axial dimension is increased and between the bearing sleeves (radial bearing surfaces). May adversely affect the rotation performance.
- At least one of the two adjacent bearing sleeves is located on the other bearing sleeve side of the radial bearing surface on the inner peripheral surface of the bearing sleeve, and has the same diameter as the radial bearing surface.
- the structure which provided the part is provided.
- the convex portion may have a slightly different diameter from the radial bearing surface as long as the coaxiality can be secured to such an extent that the rotational performance is not adversely affected. Therefore, the “convex portion having the same diameter” mentioned here includes a convex portion having a slightly different diameter.
- the shaft member is provided with a protruding portion that protrudes toward the outer diameter side, and the shaft is driven by the fluid dynamic pressure action generated in the thrust bearing gap between the end surface of the protruding portion and the end surface of the bearing sleeve.
- a thrust bearing that supports the member in a non-contact manner in the thrust direction may be provided.
- the protruding portion may be formed integrally with the shaft member, or may be fixed to the shaft member.
- the dynamic pressure generating means such as a dynamic pressure groove for generating a dynamic pressure action in the thrust bearing gap of the thrust bearing portion may be formed on at least one of the end surface of the protruding portion and the end surface of the bearing sleeve.
- a seal space may be formed on the outer peripheral side of the protrusion provided on the shaft member.
- This seal space has a function of absorbing a volume change (expansion / shrinkage) caused by a temperature change of a fluid (for example, lubricating oil) filled in the bearing device, that is, a so-called buffer function.
- a bearing member As another configuration for solving the first problem, in the present invention, a bearing member, a rotating body having a shaft member inserted into the inner periphery of the bearing member, a bearing member, and the rotating body
- the first and second thrust bearing gaps formed between the first thrust bearing gap, the first dynamic pressure groove region that generates fluid dynamic pressure in the first thrust bearing gap, and the second thrust bearing gap that generates fluid dynamic pressure in the second thrust bearing gap.
- the bearing member has two bearing sleeves arranged in the axial direction, and both of the two bearing sleeves are provided with the first dynamic pressure at both end faces.
- the first dynamic pressure groove area of one bearing sleeve faces the first thrust bearing gap
- the second dynamic pressure groove area of the other bearing sleeve is defined as a second dynamic pressure groove area. 2nd thrust Provided is a hydrodynamic bearing device characterized by facing a bearing gap.
- the bearing member since the bearing member has two bearing sleeves, it is possible to increase the moment rigidity by increasing the bearing span of the radial bearing portion, and to facilitate the manufacture of the bearing sleeve. be able to.
- Each of the above bearing sleeves has a first dynamic pressure groove region and a second dynamic pressure groove region on both end faces, and the first dynamic pressure groove region of one bearing sleeve is the first dynamic pressure groove region.
- the second dynamic pressure groove area of the other bearing sleeve faces the thrust bearing gap, which in turn means that two identical bearing sleeves are arranged in the axial direction. To do.
- each bearing sleeve can be assembled to the housing without considering the upper and lower arrangements, thereby providing a first thrust bearing gap on one end side of the bearing member and a second thrust bearing gap on the other end side, It is possible to easily form a hydrodynamic bearing device with even higher moment rigidity.
- the unit cost of parts can be reduced because the bearing sleeves can be integrated into one type, and the management cost of parts can also be reduced.
- first dynamic pressure groove region and the second dynamic pressure groove region are formed in different shapes, it is possible to easily identify the top and bottom of each bearing sleeve, thereby further facilitating the assembly. it can.
- “Different shapes” as used herein means, for example, a configuration in which one is formed by a plurality of dynamic pressure grooves arranged in a spiral shape and the other is formed by a plurality of dynamic pressure grooves arranged in a herringbone shape. Also included are those in which the number of dynamic pressure grooves arranged in is different from each other. From the viewpoint of enhancing the distinguishability, the former configuration is desirable. If the required pressure differs between the first thrust bearing gap and the second thrust bearing gap depending on the application of the hydrodynamic bearing device, the arrangement pattern of the dynamic pressure grooves may be changed accordingly. Good.
- a spacer member can be interposed between the two bearing sleeves.
- the spacer member can be formed of a material (non-porous material) having no porous structure.
- the cost can be reduced by reducing the total amount of oil.
- the volume of the seal space can be reduced as the amount of oil decreases, and the bearing span of the radial bearing portion can be further expanded, that is, the moment rigidity can be further increased.
- the hydrodynamic bearing device having the above-described configuration is a motor having the hydrodynamic bearing device, a stator coil, and a rotor magnet, and particularly high moment rigidity with high-speed rotation and weight of the rotating body.
- a motor having the hydrodynamic bearing device, a stator coil, and a rotor magnet, and particularly high moment rigidity with high-speed rotation and weight of the rotating body.
- a bearing member having a plurality of radial bearing surfaces spaced apart in the axial direction on the inner periphery, and a shaft inserted in the inner periphery of the bearing member
- a rotating body having a member, and a plurality of radial bearing portions that support the rotating body in a non-contact manner by a dynamic pressure action of fluid generated in a radial bearing gap between the radial bearing surface and the outer peripheral surface of the shaft member.
- the bearing member has a plurality of bearing sleeves arranged in the axial direction, the plurality of radial bearing surfaces are all provided on the first bearing sleeve included in the plurality of bearing sleeves, and the first
- the hydrodynamic bearing device is characterized in that the bearing sleeve is disposed on a side closer to the center of gravity of the rotating body in the axial direction.
- the rotating body refers to the entire object that rotates as the spindle of the hydrodynamic bearing device, and means an object that includes all of them if it is a member that is attached to the shaft member and can rotate integrally with the shaft member.
- a fluid bearing device when a fluid bearing device is used by being incorporated in a disk drive device such as an HDD, the shaft member and a magnet or disk constituting the drive unit, or a hub or the like for attaching the magnet or disk to the shaft member (other An assembly including all of the clampers).
- the hydrodynamic bearing device when used in a fan motor or the like, the assembly includes all of the shaft member and the magnet that constitutes the drive unit, as well as the fan that is fixed to the shaft member via a hub or the like. Refers to the body.
- the working efficiency is remarkably improved compared to the case where coaxial alignment is performed between a plurality of bearing sleeves, and this makes it possible to reduce machining costs.
- the bearing sleeve is disposed on the side closer to the axial center of gravity of the rotating body. In other words, the bearing sleeve is located as close to the axial center of gravity of the rotating body as possible.
- the radial bearing portion is formed, so that the rotating body can be supported at an appropriate location that matches the position of the center of gravity of the rotating body to be supported.
- a high moment rigidity can be ensured by compensating for the difference between the bearing spans between the radial bearing portions when the radial bearing surfaces are separately provided on the plurality of bearing sleeves.
- a second bearing sleeve having no radial bearing surface on the inner periphery is arranged on one axial direction side of the first bearing sleeve.
- the bearing member may have a housing that holds a plurality of bearing sleeves on the inner periphery, and the housing may be formed integrally with the second bearing sleeve.
- the bearing member may further include a third bearing sleeve that does not have a radial bearing surface on the inner periphery. In this case, the third bearing sleeve may be disposed on the other axial side of the first bearing sleeve.
- the bearing member has a housing formed integrally with the second bearing sleeve
- the first bearing sleeve is provided on one axial side of the second bearing sleeve
- the third shaft is provided on the other axial side.
- a receiving sleeve can also be provided.
- a configuration may also be adopted in which a thrust bearing surface is provided on each of the separated second end surfaces.
- the thrust bearing surfaces can be provided at positions as far apart as possible in the axial direction of the bearing member.
- the axial separation distance of the thrust bearing portion formed between the rotor and the rotating body can be increased as much as possible, and the moment rigidity can be further improved.
- a bearing member, a rotating body having a shaft member inserted into the inner periphery of the bearing member, and a bearing member and the shaft member are formed.
- a hydrodynamic bearing device comprising a radial bearing portion for supporting a rotating body having a shaft member in a radial direction with a fluid film generated in a radial bearing gap
- the gap width of the radial bearing gap is varied in the axial direction.
- the narrow part is arranged on the center of gravity position side of the rotating body, and at least the area of the bearing member facing the radial bearing gap is made from the deposited metal.
- the “rotary body” refers to a member that is attached to the shaft member and includes all members that can rotate integrally with the shaft member.
- the rotating body indicates a shaft member, a tissue hub provided on the shaft member, a magnet or a disk fixed to the disk hub, and a clamper.
- the rotating body when used by being incorporated in a fan motor, it refers to one including all fans, magnets, etc. fixed to the shaft member via a shaft member, hub or the like.
- the gap width of the radial bearing gap decreases, the rigidity of the fluid film formed in the radial bearing gap (bearing rigidity) increases. Accordingly, as described above, the gap width of the radial bearing gap is changed in the axial direction, and the narrow portion of the wide portion, the wide portion and the small gap width, and the narrow portion of the radial width of the rotating body is changed. If it is arranged at the center of gravity, the bearing rigidity can be increased near the center of gravity of the rotating body, while the force S can be reduced in the region away from the center of gravity. As a result, securing of bearing rigidity and lowering of torque can be achieved simultaneously, and the support accuracy of the rotating body can be increased.
- the distance between the bearing center of the radial bearing and the center of gravity of the rotating body can be shortened, and the moment stiffness can be increased.
- the above configuration is, for example, in the axial region facing the radial bearing gap, in which the shaft member is formed with a constant diameter and the bearing member is formed with a different diameter, or the shaft member is formed with a different diameter and the bearing member. Can be obtained by forming a constant diameter.
- the present invention is characterized in that at least a region (so-called radial bearing surface) facing the radial bearing gap of the bearing member is provided in the electrode part made of deposited metal.
- the electric part can be formed by a method according to electrolytic plating (electric plating) or non-electrolytic plating (battery plating). Due to the characteristics of this method, the surface on the deposition start side of the electrode part is a dense surface in which the surface shape of the master forming the surface is transferred to a micron order level with high precision. If the shape accuracy is finished, the inner peripheral surface accuracy of the bearing member can be easily increased without applying a special finishing force.
- the radial bearing surface is provided on the electrode part, particularly the deposition start surface, the width accuracy of the radial bearing gap can be easily and inexpensively increased.
- the radial bearing surface becomes a metal surface, so that the characteristic change of the radial bearing surface due to the temperature change can be suppressed, and the decrease in rotational accuracy can be suppressed as much as possible.
- the clearance width of the radial bearing clearance that can ensure the desired rotational accuracy in the above configuration is defined by the ratio of the minimum diameter clearance ⁇ of the radial bearing clearance to the shaft diameter d of the shaft member ⁇ / d According to the verification by the present inventors, it has been found that the ratio ⁇ / d should be within a range of 1/1000 ⁇ 5 / d ⁇ l / 250. The reason will be described in detail below.
- the lower limit lZlOOO of the ratio ⁇ Zd can be derived from the circularity of the outer peripheral surface of the master and the shaft member and the inner peripheral surface of the electroplating portion (cylindricity) or the like. That is, when the diameter gap ⁇ , the roundness of the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing member becomes smaller than the cylindricity, contact between the shaft member and the bearing member occurs, and a predetermined performance is secured. Becomes difficult. Although it is possible to further increase the roundness of the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing member, an increase in cost becomes unavoidable as the accuracy increases.
- the ratio ⁇ Zd is preferably ⁇ or more, considering the balance between function and cost.
- the upper limit value 1/250 of the ratio ⁇ / d can be derived from the viewpoint of rotational accuracy and moment rigidity. That is, if the minimum diameter clearance ⁇ of the radial bearing clearance is increased, the desired bearing rigidity and moment rigidity cannot be secured, and problems such as deterioration in rotational accuracy and contact between the shaft member and the bearing member occur. Therefore, the ratio ⁇ / d is desirably 1/250 or less.
- the axial direction of the radial bearing gap The ratio of the length L to the radial clearance reduction amount ⁇ / L in the axial total length of the radial bearing clearance ⁇ / L, in other words, the slope ⁇ / L should be 1/1000 ⁇ ⁇ / L ⁇ 1/500. Desirable results have been found by the inventors' extensive research. If the ratio ⁇ / L is smaller than 1/1000, it is difficult to sufficiently obtain the above-described bearing rigidity improving effect and torque reducing effect.
- the above-described hydrodynamic bearing device can be provided with a dynamic pressure generating portion for generating a fluid dynamic pressure in the radial bearing gap, whereby the radial bearing portion is constituted by a dynamic pressure bearing having excellent rotational accuracy.
- Power S can be.
- the dynamic pressure generating part is located on the inner peripheral surface of the electric iron part or the outer peripheral surface of the shaft member. It can be formed easily and with high precision simply by providing a mold corresponding to the dynamic pressure generating portion on the surface of the master used in the force / electric carcass. For this reason, it is desirable to provide the dynamic pressure generating portion on the inner peripheral surface of the electric rod portion rather than on the outer peripheral surface of the shaft member.
- the dynamic pressure generating portion can adopt various known shapes such as an inclined groove, an axial groove, or a circular arc surface.
- the region facing the dynamic pressure generating portion in the gap formed between the inner peripheral surface of the bearing member and the outer peripheral surface of the shaft member is ⁇ Radial bearing clearance.
- the bearing member has two bearing sleeves arranged in the axial direction, and each of the two bearing sleeves has a first dynamic pressure groove region and a second groove on both end faces.
- the first dynamic pressure groove region of one bearing sleeve faces the first thrust bearing gap
- the second dynamic pressure groove region of the other bearing sleeve is the second thrust bearing.
- the bearing member is provided with a plurality of bearing sleeves arranged in the axial direction
- the first bearing sleeve included in the plurality of bearing sleeves is provided with all of the plurality of radial bearing surfaces, and By disposing the first bearing sleeve on the side close to the axial center of gravity of the rotating body, a fluid that can exhibit high moment rigidity while avoiding deterioration in bearing performance due to assembly accuracy as much as possible.
- a bearing device can be provided.
- the gap width of the radial bearing gap is varied in the axial direction, and the narrow portion of the wide portion having the large gap width and the narrow portion having the small gap width is defined as the center of gravity of the rotating body.
- the area of the bearing member facing the radial bearing gap is formed in the electrode part made of deposited metal, thereby improving the width accuracy of the radial bearing surface and bearing performance including moment rigidity. Can be provided at a low cost.
- FIGS. 1 to 6 The “up and down” direction in the following description merely indicates the vertical direction in each drawing for the sake of convenience, and does not limit the installation direction, usage mode, or the like of the hydrodynamic bearing device. The same applies to other embodiments of the present invention shown in FIG.
- FIG. 1 shows a configuration example of a hydrodynamic bearing device according to the first embodiment of the present invention.
- a hydrodynamic bearing device 1 shown in the figure supports rotation of a spindle shaft in a motor incorporated in an HDD.
- the hydrodynamic bearing device 1 includes a housing 2 and a plurality of, in this case, two bearing sleeves (first bearing sleeve 3 and second bearing sleeve 4) fixed to the housing 2 at positions spaced apart from each other in the axial direction.
- a spacer member 8 disposed between the first and second bearing sleeves 3 and 4 and a shaft member 5 inserted into the inner periphery of the first and second bearing sleeves 3 and 4 are main components. As prepared.
- a first radial bearing portion R1 is provided between the inner peripheral surface 3a of the first bearing sleeve 3 and the outer peripheral surface 5a of the shaft member 5, and the inner peripheral surface 4a of the second bearing sleeve 4 is provided.
- a second radial bearing portion R2 is provided between the outer peripheral surface 5a of the shaft member 5 and the outer peripheral surface 5a.
- a first thrust bearing portion T1 is provided between the upper end surface 3b of the first bearing sleeve 3 and the lower end surface 6b of the seal member 6, and the lower end surface 4b of the second bearing sleeve 4 and the seal member 7
- a second thrust bearing portion T2 is provided between the upper end surface 7b.
- the housing 2 is formed in a substantially cylindrical shape by, for example, injection molding a resin material, and the first inner peripheral surface 7a to which the first and second bearing sleeves 3 and 4 and the spacer member 8 are fixed is It is formed on a straight cylindrical surface.
- second and third inner peripheral surfaces 2b and 2c having a diameter larger than that of the first inner peripheral surface 7a are provided at both ends of the first inner peripheral surface 7a, and the second and third inner peripheral surfaces are provided. 2b and 2c are connected to the first inner peripheral surface 2a via step surfaces 2d and 2e, respectively.
- the base resin used for the resin material forming the housing 2 may be any amorphous resin or crystalline resin as long as it can be injection-molded.
- polysulfone may be used as the amorphous resin.
- PSU polyethersulfone
- PPSU polyphenylsulfone
- PEI polyetherimide
- LCP liquid crystal polymers
- PEEK rie ether ether ketone
- PBT polybutylene terephthalate
- PPS polyphenylene sulfide
- the type of filler to be filled in the base resin is not particularly limited.
- the filler may be a fibrous filler such as glass fiber, a whisker-like filler such as potassium titanate, or a scaly shape such as my power.
- Fibrous or powdery conductive fillers such as fillers, carbon fibers, carbon black, graphite, carbon nanomaterials and metal powders can be used. These fillers may be used alone or in admixture of two or more.
- the housing 7 can also be formed of a soft metal material such as brass or an aluminum alloy, or other metal materials.
- the shaft member 5 is formed of a metal material such as stainless steel, and has a shaft shape with substantially the same diameter as a whole.
- the shaft member 5 is fixed with annular sealing members 6 and 7 as projecting portions by appropriate fixing means, for example, adhesion or press-fit adhesion (combination of press-fit and adhesion). These seal members 6 and 7 protrude from the outer peripheral surface 5a of the shaft member 5 to the outer diameter side, and are accommodated on the inner peripheral side of the second and third inner peripheral surfaces 2b and 2c of the housing 2, respectively. .
- seal members 6 and 7 are provided on the outer peripheral surface 5a of the shaft member 5 where the seal members 6 and 7 are fixed.
- the seal members 6 and 7 may be formed of a soft metal material such as brass (brass), other metal materials, or a resin material. Also, one of the seal members 6 and 7 may be integrally formed with the shaft member 5.
- the outer peripheral surface 6a of the seal member 6 forms a seal space S1 having a predetermined volume with the second inner peripheral surface 2b of the housing 2, and the outer peripheral surface 7a of the seal member 7 is the third inner peripheral surface of the housing 2.
- a seal space S2 having a predetermined volume is formed between the surface 2c.
- the outer peripheral surface 6a of the seal member 6 and the outer peripheral surface 7a of the seal member 7 are formed into tapered surfaces that are directed toward the outside of the housing 2 and gradually reduced in diameter. Therefore, the seal spaces Sl and S2 have a tapered shape that gradually decreases toward the inner side of the housing 2.
- the first and second bearing sleeves 3 and 4 are both formed into a cylindrical shape, for example, a porous body made of sintered metal, particularly a sintered metal porous body mainly containing copper, Housing 2 It is fixed to the first inner peripheral surface 2a by means such as press fitting, bonding, or press fitting.
- the bearing sleeves 3 and 4 can be formed of a metal material such as a copper alloy in addition to the sintered metal.
- the first and second bearing sleeves 3 and 4 are formed with different axial lengths. In this configuration example, the axial length L1 of the first bearing sleeve 3 is the axial length of the second bearing sleeve 4. It is larger than L2 (L1> L2).
- a region that becomes the radial bearing surface A of the first radial bearing portion R1 is formed on the inner peripheral surface 3a of the first bearing sleeve 3, and the radial bearing surface A is formed on the radial bearing surface A.
- Herringbone-shaped dynamic pressure groove 3al is formed.
- the radial bearing surface A is formed at the end portion (upper side) away from the second bearing sleeve 4.
- a belt-like convex portion B is formed on the opposite end (lower side) of the inner peripheral surface 3a of the first bearing sleeve 3 that is spaced apart from the radial bearing surface A in the axial direction.
- the convex portion B is formed to have substantially the same diameter as the hill portion that defines the dynamic pressure groove 3al.
- a region that becomes the thrust bearing surface of the first thrust bearing portion T1 is formed in a part or all of the annular region of the upper end surface 3b of the first bearing sleeve 3.
- a herringbone-shaped dynamic pressure groove 3bl is formed on the thrust bearing surface.
- a plurality of (three in the illustrated example) axial grooves 3dl are formed on the outer peripheral surface 3d at regular intervals in the circumferential direction.
- the inner peripheral surface 4a of the second bearing sleeve 4 is formed with a region to be a radial bearing surface A 'of the second radial bearing portion R2, and the radial bearing On surface A ', a herringbone-shaped dynamic pressure groove 4al is formed.
- a region that becomes the thrust bearing surface of the second thrust bearing portion T2 is formed in a part or all of the annular region of the lower end surface 4b of the second bearing sleeve 4.
- a herringbone-shaped dynamic pressure groove 4bl is formed on the thrust bearing surface.
- a plurality of (three in the illustrated example) axial grooves 4dl are formed on the outer peripheral surface 4d at equal intervals in the circumferential direction.
- a cylindrical spacer member 8 formed of, for example, a soft metal such as brass or aluminum, a resin material, or a sintered metal is interposed. And is fixed to the first inner peripheral surface 2a of the housing 2 by means such as press fitting, bonding, or press fitting.
- the inner peripheral surface 8a of the spacer member 8 is formed to have a slightly larger diameter than the inner peripheral surfaces 3a and 4a of the two bearing sleeves 3 and 4, and when the shaft member 5 rotates (during bearing operation), the shaft member Radial bearing between 5 and No gap is formed.
- a plurality of (for example, three) axial grooves 8dl are formed on the outer peripheral surface 8d at regular intervals in the circumferential direction.
- the hydrodynamic bearing device 1 including the above-described components is assembled, for example, by the following process.
- the first and second bearing sleeves 3, 4 and the spacer member 8 are fixed to the first inner peripheral surface 2a of the housing 2 in the manner shown in FIG.
- an assembly pin P as shown in FIG. 3 (A) is used to secure the coaxiality between the bearing sleeves 3 and 4 at the time of fixing.
- the inner peripheral surface 3a of the first bearing sleeve 3 is provided with a convex portion B having a diameter substantially the same as that of the radial bearing surface A on the lower end side separated from the radial bearing surface A.
- the bearing sleeve 3 it is ensured that the coaxiality is secured between both ends without deteriorating the posture.
- this assembly pin P the coaxial securing between the first and second bearing sleeves 3 and 4 is ensured.
- the upper end surface 3b of the first bearing sleeve 3 is the housing. 2 with the axial position of the first bearing sleeve 3 adjusted so that it is flush with the upper step surface 2d of the upper surface 2 or protrudes by a slight dimension ⁇ 2 from the step surface 2d. Secure to peripheral surface 2a. As shown in the figure, when the upper end surface 3b of the first bearing sleeve 3 is projected from the step surface 2d by a dimension ⁇ 2, the axial dimension between the lower end surface 6b of the seal member 6 and the step surface 2f is shown.
- the second bearing sleeve 4 is also fixed to the first inner peripheral surface 2a of the housing 2 with the same position adjustment as that of the first bearing sleeve 3.
- the shaft member 5 is inserted into the inner peripheral surfaces 3a and 4a of the first and second bearing sleeves 3 and 4 and the inner peripheral surface 8a of the spacer member 8, and the seal members 6 and 7 are inserted into the shaft member. Fix in place of 5. Note that one of the seal members 6 and 7 may be fixed to the shaft member 5 in advance before insertion, or may be integrally formed with the shaft member 5.
- the internal space of the housing 2 sealed with the seal members 6 and 7 includes the internal pores of the bearing sleeves 3 and 4 (internal pores of the porous body tissue). Therefore, for example, lubricating oil is filled as a lubricating fluid.
- the lubricating oil can be filled by, for example, immersing the hydrodynamic bearing device 1 that has been assembled in the lubricating oil in a vacuum chamber and then releasing it to atmospheric pressure.
- the radial bearing surface A of the inner peripheral surface 3a of the first bearing sleeve 3 passes through the outer peripheral surface 5a of the shaft member 5 and the radial bearing gap. opposite.
- the lubricating oil filled in the radial bearing gap is increased in pressure by the dynamic pressure action of the dynamic pressure groove 3al, and the shaft member 2 is supported in a non-contact manner in the radial direction by this pressure. .
- a radial bearing gap is formed between the convex portion B and the outer peripheral surface 5a of the shaft member 5, and an oil film is formed in the radial bearing gap by the oil that has oozed from the first bearing sleeve 3.
- the shaft member 5 is supported by the oil film so as to be rotatable in the radial direction.
- the first radial bearing portion R1 that supports the shaft member 5 rotatably in the radial direction is constituted by the dynamic pressure bearing and the perfect circle bearing.
- a dynamic pressure bearing is formed by the radial bearing surface A ′, and a second radial bearing portion R2 that supports the shaft member 5 rotatably in the radial direction is formed.
- the thrust bearing surface of the upper end surface 3b of the first bearing sleeve 3 faces the lower end surface 6b of the seal member 6 via a predetermined thrust bearing gap
- the second bearing sleeve The thrust bearing surface of the lower end surface 4b of the tube 4 faces the upper end surface 7b of the seal member 7 with a predetermined thrust bearing clearance therebetween.
- the lubricating oil filled in the thrust bearing gaps is increased by the dynamic pressure action of the dynamic pressure grooves 3bl and 4bl, so that the shaft member 5 can rotate in both thrust directions. Non-contact supported.
- the first thrust bearing portion T1 and the second thrust bearing portion T2 that support the shaft member 5 in a non-contact manner so as to be rotatable in both thrust directions are formed.
- the seal spaces Sl and S2 have a buffer function that absorbs the volume change accompanying the temperature change of the lubricating oil filled in the internal space of the housing 2, and the lubricating oil is within the range of the assumed temperature change.
- the oil level is always in the seal space Sl, S2.
- each bearing clearance radial bearing clearance of the first radial bearing portion R1 and second radial bearing portion R2, thrust bearing clearance of the first thrust bearing portion T1 and second thrust bearing portion T2
- a series of circulation passages are formed in the housing 2 by the gap between the inner peripheral surface 8a of the spacer member 8 and the outer peripheral surface 5a of the shaft member 5.
- the lubricating oil filled in the internal space of the housing 2 flows and circulates through this circulation passage, so that the pressure balance of the lubricating oil is maintained, and at the same time, the bubbles generated due to the local negative pressure are reduced. Occurrence of leakage of lubricating oil or vibration due to generation and generation of bubbles is prevented.
- one end of the fluid passage formed by the axial groove 3dl of the first bearing sleeve 3 and one end of the fluid passage formed by the axial groove 4dl of the second bearing sleeve 4 are on the atmosphere opening side, respectively. It leads to seal spaces Sl and S2. For this reason, even if bubbles are mixed in the lubricating oil for some reason, the bubbles are discharged to the open air side when circulating along with the lubricating oil, so that the adverse effects of the bubbles can be prevented more effectively.
- the axial fluid passage formed between the bearing sleeves 3, 4 and the spacer member 8 and the housing 2 is axially formed on the inner peripheral surface 2a of the housing 2. It can also be formed by providing a groove.
- the axial span between the radial bearing portions Rl and R2 can be increased to increase the load capacity against moment load, while individual bearing sleeves can be increased. Since the length of the groove can be prevented, it is possible to easily manufacture bearing sleeves 3 and 4 with the desired accuracy. In addition, since the axial lengths of the first bearing sleeve 3 and the second bearing sleeve 4 are made different from each other, the difference in the external appearance becomes clear, and the ability to reliably prevent assembly errors is ensured. Can be achieved.
- the radial bearing surface A and the inner circumferential surface 3a of the first bearing sleeve 3 having an increased axial length are separated from the radial bearing surface A at the lower end in the axial direction. Since the convex portion B having the same diameter is formed, it is possible to ensure the coaxiality between the radial bearing surfaces A and A ′ during assembly, and to prevent the deterioration of the bearing performance due to this kind of accuracy reduction.
- the convex portion B is formed in a continuous belt shape over the entire circumference of the inner peripheral surface 3a has been described. However, if the coaxiality of the bearing sleeve can be ensured, the convex portion B May be provided intermittently in the circumferential direction, for example.
- FIG. 4 shows another configuration example (second configuration example) of the hydrodynamic bearing device according to the first embodiment of the present invention.
- the main difference between the hydrodynamic bearing device 21 shown in the figure and the hydrodynamic bearing device 1 described above is that the inner peripheral surface 2a of the housing 2 has a uniform diameter and extends to the end surface of the housing 2, and accordingly, the sealing member 6 7 is relatively small in diameter.
- Such a configuration has the advantage that the shape of the housing 2 can be simplified and the diameter can be reduced compared to the hydrodynamic bearing device 1 of the first configuration example.
- the herringbone-shaped dynamic pressure groove is exemplified as the dynamic pressure generating means of the radial bearing portions Rl and R2, and the thrust bearing portions Tl and ⁇ 2, but the spiral shape and other shapes are also exemplified. Good even in dynamic pressure grooves.
- a so-called step bearing or multi-arc bearing can be used as the dynamic pressure generating means.
- FIG. 5 conceptually shows a configuration example of a spindle motor for information equipment incorporating the fluid dynamic bearing device 1 shown in FIG. 1 in the fluid dynamic bearing device according to the first embodiment of the present invention.
- This spindle motor is used for, for example, a server HDD, and includes a hydrodynamic bearing device 1, a rotor (disk hub) 12 mounted on a shaft member 5 of the hydrodynamic bearing device 1, and a radial direction, for example. It is provided with a stator coil 10 and a rotor magnet 11 which are opposed to each other through a gap in the direction (radial direction).
- the stator coil 10 is attached to the outer periphery of the bracket 9, and the rotor magnet 11 is attached to the inner periphery of the disk hub 12.
- the housing 2 of the hydrodynamic bearing device 1 is attached to the inner periphery of the bracket 9.
- the disk hub 12 holds one or more disks D such as magnetic disks.
- the stator coil 10 When the stator coil 10 is energized, the rotor magnet 11 is rotated by the electromagnetic force between the stator coil 10 and the rotor magnet 11, whereby the disk hub 12 and the disk D held by the disk hub 12 are connected to the shaft member 5. Rotates together.
- the fluid bearing device described above is not limited to a spindle motor for a disk device such as an HDD, but also a motor that rotates at a high speed and requires a load capacity for a high moment load, such as a fan motor. It can be preferably used.
- FIG. 6 shows a fan motor incorporating the hydrodynamic bearing device 1 according to the first embodiment of the present invention, and in particular, the stator coil 10 and the rotor magnet 11 are opposed to each other through a gap in the radial direction (radial direction).
- An example of a so-called radial gap type fan motor is conceptually shown.
- the motor of the illustrated example mainly has a function that the port 13 fixed to the outer periphery of the upper end of the shaft member 5 has blades on the outer peripheral surface, and the bracket 9 functions as a casing that accommodates each component of the motor. It differs from the spindle motor shown in Fig. 5 in terms of performance. Since other items are the same as those of the spindle motor shown in FIG. 5, a common reference number is assigned and a duplicate description is omitted.
- FIG. 7 conceptually shows a configuration example of a spindle motor for information equipment incorporating a hydrodynamic bearing device according to a second embodiment of the present invention.
- This spindle motor is used in a disk drive device such as an HDD.
- the spindle motor is opposed to a hydrodynamic bearing device 101 and a rotor (disk hub) 103 mounted on a shaft member 102, for example, through a radial gap.
- Data coil 104 and rotor magnet 105 The stator coil 104 is attached to the outer periphery of the bracket 106, and the rotor magnet 105 is attached to the inner periphery of the disk hub 103.
- the housing 107 of the hydrodynamic bearing device 1 is mounted on the inner periphery of the bracket 106. .
- the disk hub 103 holds one or more disks D11 such as magnetic disks.
- the stator coil 104 When the stator coil 104 is energized, the rotor magnet 105 is rotated by the electromagnetic force between the stator coil 104 and the rotor magnet 105, whereby the disk hub 103 and the disk D11 held by the disk hub 103 are exchanged with the shaft member 102. Rotates together.
- FIG. 8 shows an example of the configuration of the hydrodynamic bearing device according to the second embodiment of the present invention.
- the hydrodynamic bearing device 101 includes a fixed-side bearing member 108 and a rotating-side rotating body having a shaft member 102 inserted into the inner periphery of the bearing member 108 as main constituent members.
- the rotating body includes a shaft member 102 and seal members 109 and 110 provided at two positions in the axial direction of the shaft member 102.
- the bearing member 108 includes two bearing sleeves 181 and 181 that are spaced apart in the axial direction, and a spacer ⁇ B material 182 interposed between the bearing sleeves 181 and 181.
- a housing 107 in which both vehicle sleeves 181 and 181 and a spacer member 182 are fixed to the inner periphery.
- a first radial bearing portion R11 is provided between the inner peripheral surface 181a of the upper bearing sleeve 181 and the outer peripheral surface 102a of the shaft member 102, as will be described later.
- a second radial bearing portion R12 is provided between the inner peripheral surface 181a of the lower bearing sleeve 181 and the outer peripheral surface 102a of the shaft member 102.
- a first thrust bearing portion Ti l is provided between the upper end surface 181b of the upper bearing sleeve 181 and the lower end surface 109b of the seal member 109, and the lower end surface 181c of the lower bearing sleeve 181 and the seal member
- a second thrust bearing portion T12 is provided between the upper end surface 11 Ob of the 110.
- Shaft member 102 is formed of a metal material such as stainless steel.
- the shaft member 102 as a whole has a shaft shape with substantially the same diameter, and a relief portion 102b having a slightly smaller diameter than that of the other portion is formed at an intermediate portion thereof.
- a recessed portion for example, a circumferential groove 102c, is formed at a fixed position of the sheath members 109 and 110.
- the shaft member 102 may be a hybrid shaft (a sheath portion is made of metal and a core portion is made of resin or the like) made of a force metal and a resin, which is an integral metal product.
- the housing 107 has a cylindrical shape with openings at both ends, and an inner peripheral surface 107a thereof is formed in a straight cylindrical surface having a constant diameter in the axial direction.
- the housing 107 is, for example, a machined product of a metal material such as brass or aluminum, or an injection molded product of a resin composition.
- Resin composition There are no particular limitations on the base resin that can be used when injection molding is used, but examples include polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), and polyetherimide (PEI).
- crystalline resins such as liquid crystal polymer (LCP), polyethylene ether ketone (PEEK), polybutylene terephthalate (PBT), and polyphenylene sulfide (PPS) can be used.
- LCP liquid crystal polymer
- PEEK polyethylene ether ketone
- PBT polybutylene terephthalate
- PPS polyphenylene sulfide
- the type of filler to be filled in the above resin is not particularly limited.
- fibrous filler such as glass fiber, whisker-like filler such as potassium titanate, and scaly filling such as my strength.
- Fibrous or powdery conductive fillers such as materials, carbon fibers, carbon black, graphite, carbon nanomaterials, and metal powders can be used. These fillers may be used alone or in combination of two or more.
- the two bearing sleeves 181 and 181 are both formed of a porous body made of a sintered metal, in particular, a sintered metal porous body mainly composed of copper and formed in a cylindrical shape. Both bearing sleeves 181 and 18 1 can also be formed of a soft metal such as brass. On the outer peripheral surface 181d of the bearing sleeve 181 are provided axial grooves 181dl at equal intervals in a plurality of locations in the circumferential direction (three locations in the illustrated example).
- the inner peripheral surface 181a of the both bearing sleeves 181 and 181 is provided with a region that becomes the radial bearing surface Al l of the first and second radial bearing portions Rl l and R12, respectively, and becomes the radial bearing surface Al l.
- a plurality of dynamic pressure grooves 181al arranged in a herringbone shape are formed in a symmetrical shape in the axial direction.
- the dynamic pressure grooves 181al may be arranged in other known shapes such as a spiral shape.
- a part or all of the annular regions of the upper end surfaces 181b of the both bearing sleeves 181 and 181 include a plurality of dynamic pressure grooves 181bl arranged in a spiral shape as shown in FIG. 9B, for example.
- One dynamic pressure groove region is formed.
- a second dynamic pressure groove region composed of a plurality of dynamic pressure grooves 181cl arranged in a herringbone shape is formed. Is formed.
- the first dynamic pressure groove region of the upper bearing sleeve 181 becomes the thrust bearing surface B11 of the first thrust bearing portion T11
- the second dynamic pressure groove region of the lower bearing sleeve 181 becomes the first dynamic pressure groove region.
- the dynamic pressure grooves 181al, 181bl, and 181cl described above are all bearing sleeves. It can be formed simultaneously with the molding of the tube 181.
- a cylindrical spacer member 182 is interposed between the two bearing sleeves 181 and 181.
- the spacer member 182 is formed of a metal material such as brass or aluminum or a resin material, and the inner peripheral surface 182a thereof is formed to have a larger diameter than the inner peripheral surface 181a of the bearing sleeve 181.
- the spacer member 182 has its upper end surface 182b in contact with the lower end surface 181c of the upper bearing sleeve 181 and its lower end surface 182c in contact with the upper end surface 181b of the lower bearing sleeve 181. In this state, it is disposed at a substantially central portion in the axial direction of the inner periphery of the housing 107.
- On the outer circumferential surface 82d of the spacer member 182 are provided axial grooves 182dl at a plurality of circumferential locations (for example, three locations).
- the seal members 109 and 110 are each formed in a ring shape from a soft metal material such as brass, other metal materials, or a resin material, and are bonded and fixed to the outer peripheral surface 102a of the shaft member 102, for example.
- the adhesive applied to the shaft member 102 is filled in the circumferential groove 102c as an adhesive reservoir and solidified, whereby the adhesive strength of the seal members 109 and 110 to the shaft member 102 is improved.
- the outer peripheral surface 109a of the seal member 109 forms a first seal space S11 having a predetermined volume with the inner peripheral surface 107a on the upper end opening side of the housing 107, and the outer peripheral surface 1 of the seal member 110. 10a forms a second seal space S12 having a predetermined volume with the inner peripheral surface 107a on the lower end opening side of the housing 107.
- the outer peripheral surface 109a of the seal member 109 and the outer peripheral surface 110a of the seal member 110 are each formed into a tapered surface shape that is gradually reduced in diameter toward the outside of the bearing device.
- both the seal spaces Sll and S12 have a tapered shape that is gradually reduced in diameter in a direction approaching each other (inner direction of the housing 107).
- the lubricating oil in both the seal spaces Sl l and S 12 is narrowed by the pulling action by capillary force and the pulling action by centrifugal force during rotation (inside the housing 107).
- the shaft member 102 rotates, the lubricating oil in both the seal spaces Sl l and S 12 is narrowed by the pulling action by capillary force and the pulling action by centrifugal force during rotation (inside the housing 107).
- the lubricating oil from the inside of the housing 107 is effectively prevented.
- the first and second seal spaces Sl l, S12 have a buffer function that absorbs a volume change amount associated with a temperature change of the lubricating oil filled in the internal space of the housing 107.
- the oil level is always in both seal spaces Sl l and S12 within the assumed temperature range. In order to achieve this, the sum of the volumes of both seal spaces Sl l and S12 is set to be larger than at least the volume change accompanying the temperature change of the lubricating oil filled in the internal space.
- the assembly of the hydrodynamic bearing device 101 having the above configuration is performed as follows, for example.
- the bearing sleeves 181 and 181 and the spacer member 182 are fixed to the inner peripheral surface 107 a of the housing 107 by an appropriate means such as adhesion, press-fitting, or welding. Then, after inserting the shaft member 102 into the inner periphery of the bearing sleeves 181 and 181 and the spacer member 182, the seal members 109 and 110 are set in a predetermined manner so as to sandwich the bearing sleeves 181 and 181 and the spacer member 182. The axial gap is secured and secured to the outer periphery of the circumferential groove 102c of the shaft member 102.
- the internal space of the housing 107 sealed by the both seal members 109 and 110 includes the internal pores of the both bearing sleeves 181 and 181 as the lubricating fluid.
- Filling with the lubricating oil can be performed, for example, by immersing the fluid bearing device 101 that has been assembled in the lubricating oil in a vacuum chamber and then releasing it to atmospheric pressure.
- the radial bearing surface Al l of the inner peripheral surface 181a of the both bearing sleeve 181 is different from the outer peripheral surface 102a of the shaft member 102, respectively. Opposite through.
- dynamic pressure of lubricating oil is generated in each radial bearing gap, and the shaft member 102 is supported in a non-contact manner in a radial direction by the pressure.
- the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft member 102 in a non-contact manner so as to be rotatable in the radial direction are formed.
- the radial bearing clearance, the thrust bearing clearances of the first and second thrust bearing portions Tl l and T12), and the clearance between the inner peripheral surface 182a of the spacer member 182 and the outer peripheral surface 102a of the shaft member 102 Since a series of circulation passages are formed inside the bearing device 101, the lubricating oil flows and circulates through the circulation passages during the bearing operation. This effectively prevents the above problems. Further, one end of the axial groove 181dl of both bearing sleeves 181 communicates with the seal spaces Sl 1 and S12 on the air release side, respectively. Therefore, even if bubbles are mixed in the lubricating oil for some reason, the bubbles are discharged to the open air side when circulating along with the lubricating oil, so that the adverse effects of the bubbles can be prevented more effectively.
- the bearing sleeve has the first dynamic pressure groove region formed of the dynamic pressure groove 181bl on the upper end surface 181b and the second dynamic pressure groove region formed of the dynamic pressure groove 181cl on the lower end surface 181c.
- 181 and 181 are used, in other words, two identical bearing sleeves are used to form the bearing member 108. Therefore, the bearing sleeves 181 and 181 can be assembled to the housing 107 without considering the vertical positional relationship, and the bearing member 108 can be avoided while avoiding the problem that the fluid bearing device 101 cannot be used due to misassembly.
- the hydrodynamic bearing device 101 having excellent moment rigidity can be obtained easily and at low cost.
- the dynamic pressure grooves 181b1 on the upper end surface 181b are arranged in a spiral shape to form a first dynamic pressure groove region
- the dynamic pressure grooves 18lcl on the lower end surface 181c are arranged in a herringbone shape.
- the second dynamic pressure groove region is formed, it is possible to improve the distinguishability of both end faces and reliably prevent the situation in which the upper and lower sides of each bearing sleeve 181 are mistakenly assembled.
- the two types of bearing sleeves can be integrated into one type of bearing sleeve, the unit unit cost can be reduced and the management cost of the components can be reduced.
- dynamic pressure grooves arranged in a spiral shape are formed on the thrust bearing surface B11 (first dynamic pressure groove region) facing the first thrust bearing gap of the first thrust bearing portion T11.
- Thrust bearing surface C11 (second dynamic pressure groove area) facing the second thrust bearing gap of the second thrust bearing section T12 has dynamic pressure grooves arranged in a herringbone shape, but ensures distinction If possible, for example, the first dynamic pressure groove region and the second dynamic pressure groove region may be configured by dynamic pressure grooves arranged in the same shape with different numbers of grooves and inclination angles.
- the arrangement shape of the dynamic pressure grooves in the first dynamic pressure groove region and the second dynamic pressure groove region has been determined by focusing on only the distinctiveness.
- the first thrust bearing portion Tl 1 and the first dynamic pressure groove portion 2 The arrangement shape of the dynamic pressure grooves and the number of grooves can be varied according to the pressure required for the thrust bearing portion T12.
- any one of the seal members 109, 110 can be formed integrally with the shaft member 102, and this configuration is adopted. As a result, the assembly of the hydrodynamic bearing device 101 can be further simplified.
- dynamic pressure generating means for generating fluid dynamic pressure in the radial bearing gap
- the dynamic pressure groove may be provided on the outer peripheral surface 102a of the shaft member 102 facing the radial bearing gap.
- the dynamic pressure grooves for forming the first radial bearing portion R1 and the dynamics for forming the second radial bearing portion R2 are used.
- the pressure grooves may have different shapes or the like.
- FIG. 10 shows another configuration example (second configuration example) of the hydrodynamic bearing device according to the second embodiment of the present invention.
- the hydrodynamic bearing device 121 shown in the figure mainly includes the hydrodynamic bearing device 101 shown in FIG. 8 in that the bearing member 108 is composed of two bearing sleeves 181 and 181 and the housing 7. And the configuration is different.
- the shape of the dynamic pressure groove 181a2 is, for example, a plurality of axial directions provided at equal intervals in the circumferential direction as shown in FIG. If the groove shape is adopted, as in the configuration shown in FIG. 8, assembly can be performed without considering the vertical positions of the two bearing sleeves 181, 181.
- the radial bearing portions Rll, R12 configured by the dynamic pressure groove 181a2 of this form are so-called step bearings.
- the shape can be freely set as described above. Since the other configuration conforms to the first configuration example shown in FIG. 8, a common reference number is assigned and redundant description is omitted.
- the radial bearing portions R11 and R12 are constituted by so-called multi-arc bearings in which a plurality of arc surfaces are provided in a region to be a radial bearing surface.
- the thrust bearing portions Tl l and T12 are not located in the region that becomes the thrust bearing surface, in addition to generating the dynamic pressure action of the lubricating oil by the dynamic pressure grooves having a herringbone shape or spiral shape as described above.
- a so-called step bearing, a so-called wave bearing (where the step mold is a wave form), etc., in which a plurality of radial grooves are provided at predetermined intervals in the circumferential direction may be employed.
- the lubricating oil is exemplified as the fluid that fills the fluid bearing devices 101 and 121, but other fluids that can generate dynamic pressure in the bearing gaps,
- a gas such as air or a magnetic fluid can be used.
- the hydrodynamic bearing device 101 according to the present embodiment is used by being incorporated in a spindle motor for a disk device, but the hydrodynamic bearing device 101 according to the present embodiment is used for information equipment.
- the spindle motor it can be preferably used for a motor that rotates at high speed and requires high moment rigidity, such as a fan motor.
- FIG. 12 shows a fan motor incorporating the hydrodynamic bearing device 101 according to the second embodiment of the present invention, and in particular, the stator coil 104 and the rotor magnet 105 are opposed to each other through a radial (radial) gap.
- a radial gap type fan motor is conceptually shown.
- the rotor 133 fixed to the outer periphery of the upper end of the shaft member 102 has blades on the outer peripheral surface, and the bracket 136 is the motor. It differs from the spindle motor shown in Fig. 7 in that it functions as a casing that houses each component. Since other configurations are the same as those of the motor shown in FIG. 7, common reference numerals are assigned and duplicate descriptions are omitted.
- FIG. 13 conceptually shows a configuration example of a spindle motor for information equipment incorporating a hydrodynamic bearing device according to a third embodiment of the present invention.
- This spindle motor is used in a disk drive device such as an HDD, and is opposed to a hydrodynamic bearing device 201 that supports a rotating body 202 having a shaft member 206 in a non-contact manner in a radial direction, for example, via a radial gap.
- the stator coil 204a and the rotor magnet 204b, a force drive unit 204, and a bracket 205 are provided.
- a hub 203 is attached to the shaft member 206, and a mouth magnet 204 b is fixed to the hub 203.
- stator coil 204 a is fixed to the bracket 205.
- the housing 210 of the hydrodynamic bearing device 201 is fixed to the inner periphery of the bracket 205.
- the hub 203 holds one or a plurality of disks D21 (two in FIG. 13).
- the stator coil 204a when the stator coil 204a is energized, the rotor magnet 204b is rotated by the electromagnetic force generated between the stator coil 204a and the rotor magnet 204b.
- the fixed disk D 21 rotates integrally with the shaft member 206.
- FIG. 14 shows an example (first configuration example) of the hydrodynamic bearing device 201 according to the third embodiment of the present invention.
- a hydrodynamic bearing device 201 shown in the figure includes a bearing member 209 having a plurality of bearing sleeves and a rotating body 202 having a shaft member 206 inserted in the inner periphery of the bearing member 209 as main components.
- the bearing member 209 includes a housing 210 and a plurality of bearing sleeves fixed to the inner periphery of the housing 210, here, a first bearing sleeve 211 and a second bearing sleeve 212.
- the housing 210 is formed of, for example, a metal material or a resin material, and is located at both ends of the small-diameter surface 210a and the small-diameter surface 210a in the axial direction, and has a relatively larger diameter than the small-diameter surface 210a.
- 211 and the second bearing sleeve 212 are arranged side by side in the axial direction. Further, the large diameter surfaces 210b and 210c are connected to the small diameter surface 210a via the step surfaces 210d and 210e, respectively.
- the shaft member 206 is formed of a metal material such as stainless steel, and has a shaft shape with substantially the same diameter as a whole.
- An annular sealing member 207, 208 force S is fixed to the outer peripheral surface 206a of the shaft member 206 by an appropriate fixing means, for example, adhesion. Therefore, in this configuration example, the shaft member 206 with the seal members 207 and 208 fixed to the outer periphery, the hub 203 fixed to the shaft member 206, the rotor magnet 204b attached to the hub 203, the disk D21, and the disk D21 are connected to the hub.
- a rotating body 202 is configured with a clamper (not shown) for fixing to 203. In this configuration example, the position of the center of gravity of the rotating body 202 configured as described above is above the intermediate position in the axial direction of the bearing member 209 (on the side closer to the hub 203).
- the seal members 207 and 208 protrude from the outer peripheral surface 206a to the outer diameter side, respectively, and the inside of the nose ring 210 (the inner periphery of the large diameter surfaces 210b and 210c). Is housed.
- various means such as adhesion, press-fitting, and combined use of press-fitting and adhesion can be used.
- the sealing members 207 and 208 may be made of a soft metal material such as brass (brass) or other metal material, or a resin material. Further, the seal member 207, 208 may be integrally formed with the one-force shaft member 206. In this way, when one seal member is formed integrally with the shaft member, for example, the metal shaft member 206 can be used as an insert part, and one of the seal members can be injection-molded with resin.
- the outer peripheral surface 207a of the liner member 207 forms a seal space S21 having a predetermined volume with the large-diameter surface 210b of the housing 210, and the outer peripheral surface 208a of the seal member 208 is connected to the large-diameter surface 210c of the housing 210.
- a seal space S22 having a predetermined volume is formed between the two.
- the outer peripheral surface 207a of the seal member 207 and the outer peripheral surface 208a of the seal member 208 each have a tapered shape that is gradually reduced in diameter toward the outside of the housing 210. Therefore, the linear spaces S21 and S22 are located inside the housing 210 (on the first bearing sleeve 211 side). It has a taper shape gradually reduced toward it.
- the first bearing sleeve 211 is formed in a cylindrical shape with a porous body made of sintered metal, for example.
- the first bearing sleeve 211 is made of a sintered metal porous body mainly composed of copper and formed into a cylindrical shape, and is press-fitted and bonded to the inner peripheral surface (small-diameter surface 210a) of the housing 210. Alternatively, it is fixed by means such as press fitting.
- the first bearing sleeve 211 can also be formed of a porous body made of a non-metallic material such as resin or ceramic.
- the first bearing sleeve 211 has no internal pores.
- it can be formed of a material having a structure that has only pores of such a size that lubricating oil cannot enter and exit.
- a similar material can be selected for the second bearing sleeve 212 described later.
- a plurality of radial bearing surfaces A21, A22 are formed apart from each other in the axial direction.
- a region (dynamic pressure generating portion) in which a plurality of dynamic pressure grooves 21 lal are arranged in a herringbone shape IJ is provided on the upper radial bearing surface A21.
- a region (dynamic pressure generating portion) in which the dynamic pressure grooves 21 la2 are arranged in a herringbone shape is formed on the lower radial bearing surface A22.
- radial bearing surfaces A21 and A22 are opposed to the outer peripheral surface 206a of the vehicle bearing member 206, and the first and second radial bearing portions R21, which will be described later, between the outer peripheral surface 206a and the rotation B of the shaft shaft 206. And R22 radial bearing gaps are formed (see Fig. 14).
- the second bearing sleeve 212 is formed in a cylindrical shape with a porous body made of, for example, a sintered metal, and one axial direction of the first bearing sleeve 211 is It is disposed on the side (here, the lower side).
- the second bearing sleeve 212 is formed of a sintered metal porous body mainly composed of copper and formed in a cylindrical shape, and is press-fitted, bonded, or press-fitted to the small-diameter surface 210a of the housing 210. Fixed.
- the first bearing sleeve 211 is disposed in an upper region relative to the second bearing sleeve 212 on the inner periphery of the housing 210.
- the axial intermediate positions of the radial bearing portions R21, R22 formed between the radial bearing surfaces A21, A22 of the first bearing sleeve 211 and the outer peripheral surface 206a of the shaft member 206 opposed to the radial bearing surfaces A21, A22 are respectively
- the bearing member 209 is above the intermediate position in the axial direction (the side closer to the hub 203).
- a thrust bearing surface B21 is formed on the entire or partial region of the lower end surface 212b of the second bearing sleeve 212.
- a plurality of dynamic pressure grooves 212bl are arranged in a herringbone shape (in other words, a plurality of dynamic pressure grooves 212bl having bent portions are arranged in the circumferential direction). It is formed.
- the thrust bearing surface B21 faces the upper end surface 207b of the seal member 207 fixed to the shaft member 206.
- the first thrust bearing described later is interposed between the upper end surface 207b of the seal member 207.
- Form a thrust bearing clearance for part T21 see Fig. 14).
- a thrust bearing surface C21 is formed on the entire upper surface 21 lb of the first bearing sleeve 211 or a partial region thereof.
- a region in which a plurality of dynamic pressure grooves 2 l lbl are arranged in a herringbone shape is formed.
- This thrust bearing surface C21 faces the lower end surface 208b of the seal member 208 fixed to the shaft member 206.
- a second thrust bearing portion to be described later is formed between the lower end surface 208b of the seal member 208. Create a thrust bearing clearance for T22 (see Figure 14).
- the inner diameter of the second bearing sleeve 212 (the diameter of the inner peripheral surface 212a) is larger than the inner diameter of the first bearing sleeve 211. Therefore, in a state where the shaft member 206 is inserted into the inner circumferences of the first bearing sleeve 211 and the second bearing sleeve 212, only the inner circumferential surface 21 la of the first bearing sleeve 211 can be the radial bearing surfaces A21, A22. .
- a plurality (three in the illustrated example) of axial grooves 211dl and 212dl are formed at equal intervals in the circumferential direction on the outer peripheral surfaces 211d and 212d of the bearing sleeves 211 and 212, respectively. As a result, a fluid flow path that can communicate between the thrust bearing portion T21 and the flange 22 that are formed apart in the axial direction is formed.
- the hydrodynamic bearing device 201 having the above configuration is assembled, for example, by the following process.
- the first bearing sleeve 211 is bonded and fixed to the small diameter surface 210 a of the housing 210.
- the upper end surface 21 lb of the first bearing sleeve 211 is flush with the step surface 210e of the housing 210 located on the outer diameter side thereof, or is axially above the step surface 210e (below the seal member 208). It is fixed to the small-diameter surface 210a in the axially positioned state so as to be on the side close to the end surface 208b.
- the upper end surface 21 lb of the first bearing sleeve 211 is set. Only the thrust bearing surface C21 thus provided is capable of forming the second thrust bearing portion T22 between the lower end surface 208b of the seal member 208.
- the second bearing sleeve 212 is introduced from the lower end side of the housing 210 (one axial direction side of the first bearing sleeve 211) into the inner periphery of the small diameter surface 210a.
- the axial separation distance from the lower end surface 212b of the second bearing sleeve 212 provided with the thrust bearing surface B21 to the upper end surface 211b of the first bearing sleeve 211 provided with the thrust bearing surface C21 becomes a predetermined value.
- the axial position of the second bearing sleeve 212 with respect to the housing 210 is determined, and the second bearing sleeve 212 is fixed to the small diameter surface 210a of the housing 210 at this position. Thereby, the assembly of the bearing member 209 is completed.
- the first bearing sleeve 211 has both By simply increasing the molding accuracy when molding the radial bearing surfaces A21 and A22, the coaxiality between the radial bearing surfaces A21 and A22 can be finished with high accuracy. Therefore, compared to the conventional case where the radial bearing surfaces A21 and A22 are provided on different bearing sleeves and positioned and fixed to the housing 210, the coaxiality can be easily managed. In addition, the working efficiency can be improved as compared with the case where the inner peripheral surfaces (radial bearing surfaces) are coaxially aligned among a plurality of sleeves, thereby reducing the machining cost.
- the first bearing sleeve 211 having the plurality of radial bearing surfaces A21 and A22 is relatively rotated compared to the second bearing sleeve 212 having no radial bearing surface. It was arranged on the side close to the axial center of gravity of 202.
- the radial bearing portions R21 and R22 formed between the radial bearing surfaces A21 and A22 and the outer peripheral surface 206a of the shaft member 206 facing the radial bearing surfaces A21 and A22 rotate with respect to the axial center.
- the axial separation distance from the center of gravity of the body 202 can be reduced, and the moment rigidity of the hydrodynamic bearing device 201 can be increased.
- Thrust bearing surfaces B21, C21 are provided on the lower end surface 212b as the first end surface and the upper end surface 211b as the second end surface that is the farthest in the axial direction from the lower end surface 212b, respectively.
- the distance in the axial direction of C21 can be increased as much as possible, thereby further improving the moment rigidity.
- the second bearing sleeve 212 is in a state where the lower end surface 211c of the first bearing sleeve 211 and the upper end surface 212c of the second bearing sleeve 212 opposed to the first bearing sleeve 211 are in contact with each other. It is also possible to position and fix the second bearing sleeve 212 in a form other than this. For example, assuming a degree of variation in the axial dimension of the first bearing sleeve 211 and the second bearing sleeve 212, there is a slight gap between the bearing sleeves 211 and 212 (between the lower end surface 211c and the upper end surface 212c).
- the axial dimensions of the bearing sleeves 211 and 212 and the axial dimension of the small-diameter surface 210a of the housing 210 can be set in advance so that a gap is formed.
- the shaft member 206 is inserted into the inner periphery of each of the bearing sleeves 211 and 212, and the paper sleeves 207 and 208 are mounted on the vehicle. Fixed position of 206 [This is fixed. At this time, the seal members 207 and 208 are connected to the shaft member 206 in a state where the axial separation distance from the upper end surface 207b of one seal member 207 to the lower end surface 208b of the other seal member 208 is controlled to a predetermined value. By fixing, the sum of the thrust bearing gaps of the thrust bearing portions T21 and ⁇ 22 described later is set within a predetermined range. Either one of the seal members 207 and 208 may be integrally formed with the shaft member 206 which may be fixed to the shaft member 206 in advance before insertion.
- lubricating oil is injected into the internal space of the housing 210 sealed by the sealing members 207 and 208 as a lubricating fluid.
- the internal space of the bearing member 209 including the internal pores of the respective bearing sleeves 211 and 212 (internal pores of the porous body structure) is filled with the lubricating oil.
- the lubricating oil can be filled, for example, by immersing the fluid bearing device 201 that has been assembled in the lubricating oil in a vacuum chamber and then releasing it to atmospheric pressure.
- the two radial bearing surfaces A21, A22 formed on the inner peripheral surface 21 la of the first bearing sleeve 211 are: It opposes the outer peripheral surface 206a of the shaft member 206 via a radial bearing gap.
- the lubricating oil in the radial bearing gap is pushed into the axial center of each of the dynamic pressure grooves provided on the radial bearing surfaces A21 and A22, and the pressure rises.
- the first thrust bearing portion T21 and the second thrust bearing portion T22, which support the shaft member 206 (rotating body 202) in a non-contact manner in both thrust directions, are configured by the pressure of these oil films (see FIG. 14). .
- the seal space S21, S22 force S formed on the outer peripheral surface 207a side of the seal member 207 and the outer peripheral surface 208a side of the seal member 208 are directed toward the inner side of the housing 210. Since the taper shape is gradually reduced, the lubricating oil in both seal spaces S21 and S22 is narrowed by the pull-in action by capillary force and the pull-in action by centrifugal force during rotation. That is, it is drawn toward the inside of the housing 210. As a result, leakage of the lubricating oil from the inside of the housing 210 is effectively prevented.
- seal spaces S21 and S22 have a buffer function that absorbs the volume change accompanying the temperature change of the lubricating oil filled in the inner space of the housing 210, and within the range of the assumed temperature change, the lubricating oil The oil level is always in the seal space S21, S22.
- the configuration example of the hydrodynamic bearing device according to the third embodiment of the present invention has been described in detail.
- the present invention is not limited to the above configuration example, and the hydrodynamic bearing device having a configuration other than the above is also applicable. Applicable.
- the first bearing sleeve 211 is disposed in the upper region of the housing 210 (region on the seal member 208 side) relative to the second bearing sleeve 212 on the inner periphery of the housing 210.
- the center of gravity of the rotating body 202 depending on the position of the center of gravity of the rotating body 202 in the axial direction, it can be disposed on the opposite side (the seal member 207 side).
- the center of gravity position force of the rotating body 202 is lower than the intermediate position in the axial direction of the bearing member 209 (the far side from the hub 203). Is also possible.
- the first bearing sleeve 211 is disposed in the lower region of the housing 210 (the region on the seal member 207 side) relative to the second bearing sleeve 212, so that the radial is achieved.
- the axial separation distance between the axial center of the bearing portions R21 and R22 and the center of gravity of the rotating body 202 is reduced, and thereby high moment rigidity can be obtained.
- FIG. 18 shows an example of this, and a sleeve-like projecting portion 210 f projecting from the small diameter surface 210 a of the housing 210 toward the inner diameter side is formed integrally with the housing 210.
- the inner diameter of the protrusion 210f (the diameter of the inner peripheral surface 210fl) is larger than the inner diameter of the first bearing sleeve 211. Therefore, in the state where the shaft member 206 (see FIG.
- the inner diameter of the first bearing sleeve 211 is the same as in the above configuration example.
- peripheral surface 211a is radial bearing surface A2 1, can be A22.
- a thrust bearing surface B21 having a shape shown in FIG. 16, for example, is formed on the lower end surface 210f2 of the protruding portion 210f.
- the inner peripheral surface 210fl of the protrusion 210f and the large-diameter surface 210b of the housing 210 are connected via the lower end surface 210f2.
- the projecting portion 210f is provided with an axial through hole 210f4, and the through hole 210f4 and the axial groove 21ldl form a fluid flow path.
- the number of parts can be further reduced, and the assembly process force of the bearing member 209 can be achieved only by positioning and fixing the first bearing sleeve 211, thereby simplifying the work process. Can be achieved.
- the bearing member 209 may further include a third bearing sleeve that does not have the radial bearing surfaces A21, A22 on the inner periphery.
- FIG. 19 shows an example.
- the bearing member 209 includes a first bearing sleeve 211 and a housing 210 having a projecting portion 210f as a second bearing sleeve, and the projecting portion 210f (second bearing sleeve). ) Is further provided with a third bearing sleeve 213.
- the inner diameter of the protrusion 210 f and the inner diameter of the third bearing sleeve 213 are both larger than the inner diameter of the first bearing sleeve 211.
- the inner peripheral surface 21 la of the first bearing sleeve 211 can be the radial bearing surfaces A21, A22.
- the thrust bearing surface B21 is provided on the lower end surface 213b of the third bearing sleeve 213.
- An axial groove 213dl is formed on the outer peripheral surface 21 3d of the third bearing sleeve 213.
- the axial groove 213dl and the through hole 210f4 of the protrusion 210f and the axial groove 21 of the first bearing sleeve 211 are formed.
- the above-described fluid flow path is configured with ldl.
- any of the thrust bearing surfaces B21 and C21 is formed of sintered metal.
- Abundant lubricating oil can be stably supplied to the gap. For this reason, it is possible to prevent oil shortage in the bearing gap as much as possible and to stably exhibit a high oil film forming ability. Further, as described above, by forming a part of the bearing sleeve integrally with the housing 210, there is also an effect of adjusting the amount of lubricating oil filled in the bearing internal space.
- FIG. 20 shows an example of this.
- the inner peripheral surface of the housing 210 has a uniform diameter (having an inner peripheral surface 210g having a constant diameter), and accordingly, the sealing members 207 and 208 have a relatively small diameter.
- the configuration is different from that of the hydrodynamic bearing device 201 shown in FIG. In this case, there is an advantage that the shape of the housing 210 can be simplified and the diameter can be reduced by using the housing 210 having a strong shape.
- the arrangement region (dynamic pressure generating portion) of the dynamic pressure grooves 211al and 21 la2 is used as the inner peripheral surface 211a of the first bearing sleeve 211 having the radial bearing surfaces A21 and A22, and the thrust bearing.
- the case where it is formed on the upper end surface 211b having the surface C21 or the lower end surface 212b of the second bearing sleeve 212 having the thrust bearing surface B21 has been described, but it is not necessary to be limited to this form.
- the dynamic pressure generating portion composed of the dynamic pressure grooves 211al and 21 la2 can be formed on the outer peripheral surface 206a of the shaft member 206 facing the radial bearing surfaces A21 and A22, and also composed of the dynamic pressure grooves 212bl and 21 lbl.
- the dynamic pressure generating portion may be formed on the upper end surface 207b of the seal member 207 facing the thrust bearing surfaces B21 and C21 and the lower end surface 208b of the seal member 208.
- the dynamic pressure generating portion of the form described below can be formed not only on the bearing member 209 side but also on the shaft member 206 and the seal members 207 and 208 facing each other.
- radial bearing portions R21 and R22 although not shown, so-called step-like dynamic pressure generating portions in which axial grooves are arranged at a plurality of locations in the circumferential direction, or in the circumferential direction.
- a so-called multi-arc bearing in which a plurality of arc surfaces are arranged and a wedge-shaped radial clearance (bearing clearance) is formed between the outer peripheral surfaces 206a of the opposing shaft members 206 may be adopted.
- one or both of the thrust bearing portions T21, ⁇ 22 is provided with a plurality of radial groove-shaped dynamic pressure grooves in the circumferential direction in the region that becomes the thrust bearing surfaces B21, C21, which are not shown.
- a so-called step bearing or corrugated bearing provided at regular intervals can also be used.
- the shaft member 206 rotates and is supported by the bearing member 209. Conversely, the bearing member 209 side rotates and rotates the shaft member 206.
- the present invention can also be applied to a structure that is supported on the side.
- the lubricating oil is exemplified as the fluid that fills the inside of the hydrodynamic bearing device 201 and causes the dynamic bearing action of the fluid in the radial bearing gap or the thrust bearing gap.
- a fluid capable of generating a dynamic pressure action in the bearing gap for example, a gas such as air, a fluid lubricant such as a magnetic fluid, or lubricating grease may be used.
- a hydrodynamic bearing device according to a fourth embodiment of the present invention will be described below with reference to Figs.
- FIG. 21 is an axial cross-sectional view showing an example (first configuration example) of the hydrodynamic bearing device 301 according to the fourth embodiment of the present invention.
- a fluid dynamic bearing device 301 shown in the figure is used by being incorporated in a spindle motor such as an HDD, for example, and includes a bearing member 305 and a rotating body 302 having a shaft member 303 inserted in the inner periphery of the bearing member 305. It is provided as a main component.
- the hydrodynamic bearing device 301 shown in the figure has radial bearing gaps separated in two axial directions, and two radial bearing gaps Crl and Cr2 and the region between them, respectively. In this configuration, the gap width is gradually reduced upward in the axial direction.
- the rotating body 302 is made of, for example, a metal material such as stainless steel, and has a shaft member 303 formed with a constant diameter over the entire length in the axial direction, and a hub (disk hub) 304 provided on the outer periphery of the upper end of the shaft member 303. And a disc (not shown), a rotor magnet, and a clamper for fixing the disc to the hub 304.
- the center of gravity (axial center) G of the rotating body 302 having a powerful structure is located above the axial center of the bearing member 305 (side closer to the hub 304).
- the outer peripheral surface 303a of the shaft member 303 is formed into a smooth surface, and the lower end surface 303b is formed into a convex spherical shape.
- the bearing member 305 was formed by injection molding using a bottomed cylindrical electrode part 306 made of deposited metal formed by electroplating, which will be described later, and a molten material using the electrode part 306 as an insert part. It is comprised with the covering part 307.
- a taper surface 305c that gradually increases in the axial direction is formed in the upper end opening of the inner periphery of the bearing member 305. Between the tapered surface 305c and the outer peripheral surface 303a of the shaft member 303, ring A shaped seal space S3 is formed.
- the inner peripheral surface 305a region below the tapered surface 305c has regions (regions filled in the drawing) that become the radial bearing surfaces 308 and 309 of the radial bearing portions R31 and R32. It is provided at two locations above and below.
- the radial bearing surfaces 308 and 309 are each provided with a plurality of dynamic pressure grooves 308a and 309a arranged in a herringbone shape as dynamic pressure generating portions.
- the upper dynamic pressure groove 308a is formed axially asymmetric with respect to the axial center m of the upper and lower inclined groove regions, and the axial dimension XI of the upper region from the axial center m is the axial dimension X2 of the lower region.
- the lower dynamic pressure grooves 309a are formed symmetrically in the axial direction, and the axial dimensions of the upper and lower regions thereof are equal to the axial dimension X2.
- the pulling force of the lubricating oil (bon pin daka) by the dynamic pressure groove is relatively larger in the upper dynamic pressure groove 308a than in the lower symmetrical dynamic pressure groove 9a.
- the upper dynamic pressure groove 308a can be formed in an axially symmetric shape like the lower dynamic pressure groove 309a.
- the dynamic pressure grooves can be arranged in a spiral shape or other known shapes in addition to the herringbone shape. For simplification of the drawing, the dynamic pressure groove is omitted in FIG.
- a part or all of the annular region of the inner bottom surface 305b of the bearing member 305 serves as a thrust bearing surface of the thrust bearing portion T3.
- the region to be applied is formed on a smooth plane.
- the inner peripheral surface 305a of the bearing member 305 including the radial bearing surfaces 308 and 309 is formed in a taper shape with the inner diameter gradually reduced upward in the axial direction.
- each upper end portion is a narrow portion with a small gap width Dl.
- each lower end becomes a wide part D2 with a large gap width.
- the force depicted by exaggerating the degree of inclination of the inner peripheral surface 305a is a radius between the narrow portion D1 and the wide portion D2 of the radial bearing gap Crl (or Cr2).
- Ratio of clearance reduction amount ⁇ and axial separation distance between both parts (axial length of radial bearing clearance) L, that is, inclination ⁇ ZL is ⁇ / L ⁇ lZ500 (inclination angle with respect to axis) For example, 0.11 ° or less). It is difficult to mass-produce a taper surface with a very small inclination angle by general machining, but if it is electroplating, such a taper surface is also low-cost for the reasons described later. It can be mass-produced with high accuracy.
- the bearing member 305 includes a step (Z1) of manufacturing a master which is a molding base of the electric part 306, a step (Z2) of masking a part of the master surface with an insulating material, and a master subjected to masking.
- a solid shaft master made of a conductive material, for example, stainless steel, nickel chrome steel, other nickel alloy, or chromium alloy that has been hardened. 311 is formed.
- the master 311 can also be formed of a non-metallic material such as ceramic that has been subjected to a conductive treatment (for example, forming a conductive film on the surface).
- a molding portion N that molds the electroplating portion 306 is provided on one end surface of the master 311 and a partial region of the outer peripheral surface continuous thereto.
- the forming part N has a shape in which the concave / convex pattern inside the electroplating part 306 is inverted, and a hill part between the dynamic pressure grooves 308a and 309a is formed in two axially spaced portions on the outer peripheral surface thereof.
- a row of mold parts 311al and 311a2 is formed in the circumferential direction.
- the shapes of the mold parts 311al and 31la2 may correspond to the shape of the dynamic pressure groove, and may be formed in a spiral shape or the like.
- the surface accuracy of the molded part N including the mold parts 311al and 31 la2 directly affects the precision of the electric part 306. Therefore, it is desirable that the forming part N be finished with as high accuracy as possible in accordance with various precisions required for the electric part 306.
- masking is performed on the outer surface of the master 311 except for the molding portion N, and a masking portion 312 is formed.
- a material having insulation properties and corrosion resistance to the electrolyte solution can be suitably used in consideration of the electroplating process described later.
- Master 311 is immersed in an electrolyte solution containing metal ions such as Ni and Cu. Then, the current is applied to the master 311 and the target metal is deposited (electrolytic deposition) on the forming part N of the master 311.
- the electrolyte solution may contain a sliding material such as carbon or fluorine-based particles, or a stress relaxation material such as saccharin.
- the type of electrodeposited metal is appropriately selected according to physical properties such as hardness and fatigue strength required for the bearing surface and chemical properties.
- an electrical member 313 is formed in which the electrical part 306 is attached to the molding part N of the master 311.
- the shape 311al and 31 la2 of the shape are transferred onto the inner peripheral surface of the electric rod portion 306, and are formed apart from each other in the axial direction of the plurality of dynamic pressure grooves 308a and 309a shown in FIG.
- the optimum thickness according to the application for example, 10 ⁇ ! It is formed to a thickness of ⁇ 200 ⁇ m.
- the electric part 306 may be formed by a method according to the electroless plating (electrical plating). it can.
- the electric member 313 is disposed as an insert part in a predetermined mold, and then insert molding is performed using a molten material, for example, a molten resin.
- a molten material for example, a molten resin.
- any of a crystalline resin and an amorphous resin can be used as the base resin.
- the crystalline resin include liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyacetal (POM), polyamide (PA), etc.
- LCP liquid crystal polymer
- PPS polyphenylene sulfide
- PEEK polyetheretherketone
- POM polyacetal
- PA polyamide
- PPSU polysulfone sulfone
- PES polyethersulfone
- PEI polyetherimide
- PAI Polyamideimide
- One or two or more kinds of fillers such as reinforcing materials (fibrous and powdery forms), lubricants, conductive materials and the like can be added to the above-described base resin as necessary. .
- the covering portion 307 can also be made of a molten material other than resin, for example, a low melting point metal such as magnesium alloy or aluminum alloy.
- a low melting point metal such as magnesium alloy or aluminum alloy.
- MIM molding in which degreasing and sintering are performed after injection molding with a mixture of metal powder and binder, and so-called CIM molding using a mixture of ceramic and binder can also be used. It is.
- the surface from which deposition starts on the master 311, that is, the inner surface of the electroplating part 306, is a dense surface to which the surface accuracy of the master 311 (molded part N) is transferred with high accuracy.
- the surface on the deposition end side, that is, the outer surface of the electroplating portion 306 is formed into a rough surface.
- the electric member 313 formed as described above is transferred to the separation step, and is separated into the bearing member 305 in which the electric portion 306 and the covering portion 307 are integrated, and the master 311.
- this separation step for example, by applying an impact to the master 311 or the bearing member 305, the inner peripheral surface of the electric part 306 is slightly expanded in diameter, and the electric part 306 is peeled off from the surface of the master 311. . Accordingly, the master 311 can be separated from the bearing member 305, and when the master 311 is pulled out, the bearing member 305 as a finished product is obtained.
- a peeling means for the electric wire part 306 for example, a method by heating (or cooling) the electric wire part 306 and the master 311 to cause a difference in thermal expansion between the two, Alternatively, a method using both means (impact and heating) in combination can be used.
- the bearing member 305 is formed in a bottomed cylindrical shape, and the inner peripheral surface 305a is formed in a tapered shape having a direction toward the opening and gradually reduced in diameter.
- the separation of 311 is so-called unreasonable.
- the master 311 is forcibly removed when the dynamic pressure grooves 308a and 309a are provided on the inner peripheral surface 305a of the bearing member 305 as in this configuration example, the dynamic pressure grooves 308a and 309a There is a risk of damage and consequently deterioration of bearing performance.
- the inclination ⁇ / L of the inner peripheral surface 305a including the radial bearing surfaces 308 and 309 of the bearing member 305 is set to a minute value of about ⁇ / L ⁇ 1/500. Therefore, the degree of unreasonableness is very small.
- the electrode portion 306 constituting the bearing member 305 is formed to be extremely thin and the electrode portion 306 and the covering portion 307 are firmly fixed. The part 306 is deformed following the deformation of the resin covering part 307 having excellent elasticity. From the above, damage to the dynamic pressure grooves 308a and 309a due to separation of the master 311 can be effectively prevented.
- a shaft member 303 (rotating body 302) prepared separately from the pulled out master 311 is inserted into the inner periphery of the bearing member 305 formed as described above, and fluid is introduced into the inner space of the bearing member 305 as a fluid.
- the hydrodynamic bearing device 301 shown in FIG. 21 is completed by filling the lubricating oil.
- the high-precision bearing member 305 can be mass-produced stably and at low cost.
- the pulling force due to the capillary force acts on the lubricating oil in the seal space S3.
- the lubricating oil is always maintained within the range of the seal gap S3.
- the radial bearing surfaces 308 and 309 spaced apart at two locations above and below the inner peripheral surface 305a of the bearing member 305 are respectively It faces the outer peripheral surface 303a of the shaft member 303 via radial bearing gaps Crl and Cr2.
- the shaft member 303 rotates, dynamic pressure of the lubricating oil is generated in the radial bearing gaps Crl and Cr2, and the oil film rigidity of the lubricating oil film formed in the radial bearing gaps Crl and Cr2 is increased by the pressure, and the shaft member 303 is supported in a non-contact manner so as to be rotatable in the radial direction.
- the first radial bearing portion R31 and the second radial bearing portion R32 that support the rotating body 302 having the shaft member 303 in a non-contact manner so as to be rotatable in the radial direction are formed.
- a thrust bearing portion T3 that rotatably supports the rotating body 302 having the shaft member 303 in the thrust direction. It is formed.
- the rigidity of the oil film (bearing rigidity) formed in the radial bearing gap increases as the gap width decreases. Therefore, in the above configuration in which the clearance width of the radial bearing gap is gradually decreased upward in the axial direction, the narrow portion having a small clearance width in the radial bearing clearance is used.
- the oil film rigidity at Dl is higher than the oil film rigidity at the wide part D2 where the gap width is large.
- the center of gravity G force of the rotating body 302 is positioned above the center of the bearing member 305 in the axial direction, so that the bearing rigidity can be increased in a region near the center of gravity G of the rotating body 302. The bearing rigidity can be lowered in the region away from the center of gravity G.
- the radial bearing gap is provided at two locations separated in the axial direction. Therefore, the bearing centers of the radial bearing portions R31 and R32 are located above the axial center of the bearing member 305. Will be. Accordingly, the distance between the bearing center of the radial bearing portion and the center of gravity G of the rotating body 302 can be shortened, and the structure is excellent in load capacity (moment rigidity) against moment load.
- the radial clearance reduction amount ⁇ between the narrow part Dl and the wide part D2 of the radial bearing gap Crl (or Cr2) described above and the axial separation distance between the two parts (the axis of the radial bearing gap (Direction length) Ratio to L (slope) ⁇ / L is preferably 1/1000 ⁇ ⁇ / L ⁇ 1/500. If the value of the inclination ⁇ / L is smaller than 1/1000, it is difficult to sufficiently obtain the effect of improving the bearing rigidity and the effect of reducing the torque.
- the minimum diameter clearance of the radial bearing clearance Crl (inner diameter dimension in the narrow portion D1) ⁇ is the ratio ⁇ / d to the shaft diameter d of the shaft member 303 is 1 / 1000 ⁇ 5 / d ⁇
- the lower limit value 1/1000 of the ratio ⁇ / d can be derived from the roundness “cylindricity” of the outer peripheral surface of the master 311 and the shaft member 303 and the inner peripheral surface of the electric electrode part 306.
- the diameter gap ⁇ force When the roundness and the cylindricity of the outer peripheral surface 303a of the shaft member 303 and the inner peripheral surface 305a of the bearing member 305 become smaller than the roundness and the cylindricity, contact occurs between the shaft member 303 and the bearing member 305. It becomes difficult to ensure performance. Although it is possible to further increase these various accuracies, cost increases are unavoidable as the accuracy increases. Therefore, considering the balance between functionality and cost, the ratio ⁇ / d should be 1/1000 or more. On the other hand, the upper limit of the ratio ⁇ / d 1/250 Can be derived from the viewpoint of rotational accuracy and moment rigidity.
- the ratio ⁇ / d is desirably 1/250 or less.
- the inner peripheral surface 305b of the bearing member 305 is a radial bearing surface 308, 309, and the inner bottom surface 305b (thrust bearing surface) in sliding contact with the lower end surface 303b of the shaft member 303.
- the accuracy of the inner peripheral surface 305a and the inner bottom surface 305b of the bearing member 305 can be easily increased, and the width accuracy of the radial bearing gaps Crl and Cr2 can be managed with high accuracy.
- the radial bearing surfaces 308 and 309 and the thrust bearing surface are metal surfaces, the radial bearing parts R31 and R32 can suppress changes in characteristics due to temperature changes and wear, and the thrust bearing part T3 has wear resistance. It can improve the sex. Based on the above, it is possible to suppress an increase in the amount of swing of the rotating body 302 and a decrease in the rotational performance due to resonance when the hydrodynamic bearing device 301 is subjected to vibration or impact, and to maintain high rotational performance. Is possible.
- FIG. 25 shows a second configuration example of the hydrodynamic bearing device according to the fourth embodiment of the present invention.
- the hydrodynamic bearing device 321 shown in the figure differs from the hydrodynamic bearing device 301 shown in FIG. 21 mainly in that the hub 304 constituting the rotating body 302 is provided below the bearing member 305, and the center of gravity G of the rotating body 302 Is located below the bearing member 305, and correspondingly, the inner diameter dimension of the bearing member 305 is formed so as to gradually decrease downward in the axial direction.
- a sealing space can also be formed at both ends of the force bearing member 305, which is not shown, as in the embodiment shown in FIG.
- Fig. 26 shows a third configuration example of the hydrodynamic bearing device according to the fourth embodiment of the present invention.
- the inner peripheral surface force of the bearing member 305 is relatively in the axial direction but not in the taper shape in which the inner diameter dimension as shown in FIGS. 21 and 25 is gradually reduced to one of the axial directions.
- the first inner peripheral surface 305d having a small diameter and the second inner peripheral surface 305e having a larger diameter than the first inner peripheral surface 305d are partitioned.
- a radial bearing surface 308 is provided in a part or all of the axial direction region of the first inner peripheral surface 305d, and a radial bearing surface 309 is provided in a part or all of the axial region of the second inner peripheral surface 305e.
- the entire radial bearing gap Cr 1 formed between the upper radial bearing surface 308 and the outer peripheral surface 303a of the shaft member 303 becomes the narrow portion D1
- the lower radial bearing surface 309 The entire radial bearing gap Cr2 formed between the outer peripheral surface 303a of the shaft member 303 becomes the wide portion D2.
- FIG. 27 shows a fourth configuration example of the hydrodynamic bearing device according to the fourth embodiment of the present invention.
- a bearing member 345 is mainly provided with a main body portion 345a having radial bearing surfaces 308 and 309, and protruding above the main body portion 345a, and an outer peripheral surface 303a of the shaft member 303.
- 21 is different from the hydrodynamic bearing device 301 shown in FIG. 21 in that it is partitioned by a substantially hemispherical protrusion 345b that forms a seal space S3 and a lubricating oil reservoir 346 therebetween.
- the side part which comprises the main-body part 345a the whole inner diameter dimension is reducing gradually toward the axial direction upper direction.
- the bearing member 345 can be formed, for example, as follows. First, in accordance with the molding procedure of the bearing member 305 described above, the side part of the main body part 345a and the protruding part 345b are molded in a state parallel to the axis, and separated from the master. Next, in a state where the molds following the shapes of the main body portion 345a and the three projecting portions 45b as finished products are heated, a pressing force is applied from the outer diameter side of the bearing member 345, and the side portion of the main body portion 345a. And the projecting portion 345b are deformed in the inner diameter direction to form a kind of plastic deformation state. Then, when the mold is opened, a bearing member 345 shown in the figure is obtained.
- the shaft member 303 is formed to have a constant diameter over the entire length in the axial direction, and the inner diameter dimension of the bearing member 305 is made different in the axial direction, so that the radial width of the radial bearing gap is reduced in the axial direction.
- the configuration in which fluid dynamic pressure is generated by the herringbone-shaped or spiral-shaped dynamic pressure grooves is exemplified as the radial bearing portions R31, R32.
- the present invention is not limited to this. Les.
- one or both of the radial bearing portions R31 and R32 can be configured as a so-called multi-arc bearing or a step bearing.
- These bearings can be obtained by forming a plurality of circular arc surfaces and axial grooves as dynamic pressure generating portions on the radial bearing surfaces 308 and 309 of the bearing member 305, for example. Since the method for forming these dynamic pressure generating portions is in accordance with the respective steps in forming the dynamic pressure grooves 308a and 309a, detailed description thereof is omitted.
- Fig. 28 shows an example of a case where one or both of the radial bearing portions R31, R32 is formed of a multi-arc bearing.
- the regions that become the radial bearing surfaces 308 and 309 on the inner peripheral surface of the bearing member 305 are configured by three arc surfaces 351 (La, loose three arc bearings).
- the centers of curvature of the three arcuate surfaces 351 are offset by an equal distance from the shaft center O of the bearing member 305 (shaft member 303).
- the radial bearing gap is a wedge-shaped gap Cr3 that gradually decreases in a wedge shape in both circumferential directions.
- the bearing member 305 and the shaft member 303 rotate relative to each other, the lubricating oil in the radial bearing clearance is pushed into the minimum clearance side of the wedge-shaped clearance Cr3 according to the relative rotation direction, and the pressure increases. .
- the bearing member 305 and the shaft member 303 are supported in a non-contact manner by such a dynamic pressure action of the lubricating oil.
- a deep axial groove called a separation groove may be formed at the boundary between the three arcuate surfaces 351.
- Fig. 29 shows another example in which one or both of the radial bearing portions R31, R32 is formed of a multi-arc bearing.
- the radial force on the inner peripheral surface of the bearing member 305 is composed of three arcuate surfaces 351, which are the radial bearing surfaces 308 and 309 (relatively three arcuate bearings).
- the radial bearing gap is a wedge-shaped gap Cr3 that gradually decreases in a wedge shape with respect to one circumferential direction.
- the multi-arc bearing having such a configuration is sometimes referred to as a taper bearing.
- the three arc surfaces 35 A deeper axial groove called a separation groove 352 is formed at the boundary between them.
- Fig. 30 shows another example in the case where one or both of the radial bearing portions R31, R32 is formed of a multi-arc bearing.
- a predetermined region ⁇ force on the minimum clearance side of the three arcuate surfaces 351 is a concentric arcuate surface with the center O of the bearing member 305 (shaft member 303) as the center of curvature. It is configured. Accordingly, the radial bearing gap (minimum gap) is constant in each predetermined region ⁇ .
- the multi-arc bearing having such a configuration is sometimes referred to as a taper flat bearing.
- FIG. 31 shows an example in which one or both of the radial bearing portions R31 and R32 are configured by step bearings.
- a plurality of axial groove-shaped dynamic pressure grooves 353 are provided at predetermined intervals in the circumferential direction in the region that becomes the radial bearing surfaces 308 and 309 on the inner peripheral surface of the bearing member 305 (electrical part 306). ing.
- the radial bearing portions R31 and R32 are provided with two radial bearing portions separated in the axial direction.
- the radial bearing portions have three locations on the upper and lower regions of the inner peripheral surface of the bearing member 305. It is good also as a structure which provided the above radial bearing part.
- the multi-arc bearing shown in FIGS. 28 to 30 is composed of a force S that is a so-called 3-arc bearing, not limited to this, but a so-called 4-arc bearing, 5-arc bearing, and more than 6 arc surfaces.
- a multi-circular bearing may be used.
- the dynamic pressure generating portion is formed on the radial bearing surfaces 308 and 309 of the electric rod portion 306 constituting the bearing member 305 is exemplified, but the shaft facing the radial bearing surfaces 308 and 309 is exemplified.
- a dynamic pressure generating portion may be provided on the outer peripheral surface 303a of the member 303.
- the regions that serve as the radial bearing surfaces 308 and 309 of the electrode portion 306 are formed in a cylindrical surface shape having no irregularities.
- a dynamic pressure generating portion is provided on the radial bearing surfaces 308 and 309 of the electric rod portion 306 constituting the bearing member 305 or the outer peripheral surface 303a of the shaft member 303, and the radial bearing gap is provided at the dynamic pressure generating portion.
- the radial bearing parts R31 and R32 are composed of dynamic pressure bearings by generating fluid dynamic pressure on the radial surface 308 and 309
- the radial bearing portions R31 and R32 can also be configured with perfect circular bearings (not shown).
- the thrust bearing portion T3 is configured by a pivot bearing
- the lower end of the shaft member 303 is a flat surface, and this flat surface or the end surface of the bearing member facing the flat surface is used.
- the thrust bearing portion can also be constituted by a dynamic pressure bearing (not shown).
- the lubricating oil is used as the lubricating fluid filling the internal space of the hydrodynamic bearing device.
- other fluids capable of forming a fluid film such as lubricating grease, magnetic fluid, air, etc. Gas or the like can also be used.
- the fluid dynamic bearing device described above boasts high rotational accuracy, it is suitable as a bearing for various motors that require high rotational performance, such as spindle motors for disk devices such as HDDs and fan motors for personal computers. Can be used for
- FIG. 1 is a cross-sectional view showing a first configuration example of a hydrodynamic bearing device according to a first embodiment of the present invention.
- FIG. 2A is a top view showing a state in which a bearing sleeve is fixed to a housing
- FIG. 2B is a sectional view thereof
- FIG. 2C is a bottom view thereof.
- FIG. 3A is a schematic view showing the assembly process of the bearing sleeve
- FIG. 3B is an enlarged sectional view showing an upper portion of the housing.
- FIG. 4 is a cross-sectional view showing a second configuration example of the hydrodynamic bearing device according to the first embodiment.
- FIG. 5 is a cross-sectional view conceptually showing a spindle motor incorporating a hydrodynamic bearing device.
- FIG. 6 is a cross-sectional view conceptually showing a fan motor incorporating a fluid dynamic bearing device.
- FIG. 7 is a sectional view conceptually showing a spindle motor incorporating a fluid dynamic bearing device.
- FIG. 8 is a cross-sectional view showing a first configuration example of a hydrodynamic bearing device according to a second embodiment of the present invention.
- FIG. 9A is a longitudinal sectional view of the bearing sleeve
- FIG. 9B is a view showing an upper end face of the bearing sleeve
- FIG. 9C is a view showing a lower end face of the bearing sleeve.
- FIG. 10 is a cross-sectional view showing a second configuration example of the hydrodynamic bearing device according to the second embodiment.
- FIG. 11 is a longitudinal sectional view showing another configuration example of the bearing sleeve.
- FIG. 12 is a cross-sectional view conceptually showing a fan motor incorporating a hydrodynamic bearing device.
- FIG. 13 is a sectional view conceptually showing a spindle motor incorporating a hydrodynamic bearing device.
- FIG. 14 is a cross-sectional view showing a first configuration example of a hydrodynamic bearing device according to a third embodiment of the present invention.
- FIG. 15 is a cross-sectional view of a bearing member.
- FIG. 16 is an end view of the bearing member shown in FIG. 15 as viewed from the direction of arrow a.
- FIG. 17 is an end view of the bearing member shown in FIG. 15 viewed from the direction of arrow b.
- FIG. 18 is a cross-sectional view showing another configuration of the bearing member.
- FIG. 19 is a cross-sectional view showing another configuration of the bearing member.
- FIG. 20 is a cross-sectional view showing a second configuration example of the hydrodynamic bearing device according to the third embodiment.
- FIG. 21 is an axial cross-sectional view showing a first configuration example of a hydrodynamic bearing device according to a fourth embodiment of the present invention.
- FIG. 22 is a cross-sectional view of a bearing member.
- FIG. 23A is a perspective view of the master
- FIG. 23B is a perspective view showing a state in which the master is masked
- FIG. 23C is a perspective view of the electronic member.
- FIG. 24 is a cross-sectional view of a bearing member immediately after insert molding.
- FIG. 25 is a cross-sectional view showing a second configuration example of the hydrodynamic bearing device according to the fourth embodiment.
- FIG. 26 is a cross-sectional view showing a third configuration example of the hydrodynamic bearing device according to the fourth embodiment.
- FIG. 27 is a cross-sectional view showing a fourth configuration example of the hydrodynamic bearing device according to the fourth embodiment.
- FIG. 28 is a cross-sectional view including a shaft when the radial bearing portion is constituted by a multi-arc bearing.
- FIG. 29 is a cross-sectional view including a shaft when the radial bearing portion is constituted by a multi-arc bearing.
- FIG. 30 is a cross-sectional view including a shaft when the radial bearing portion is constituted by a multi-arc bearing.
- FIG. 31 is a cross-sectional view including a shaft when the radial bearing portion is constituted by a step bearing.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020087024858A KR101413550B1 (ko) | 2006-03-24 | 2007-03-22 | 유체 베어링 장치 |
KR1020137025904A KR101460573B1 (ko) | 2006-03-24 | 2007-03-22 | 유체 베어링 장치 |
US12/293,953 US8215843B2 (en) | 2006-03-24 | 2007-03-22 | Fluid dynamic bearing device |
CN2007800100900A CN101405513B (zh) | 2006-03-24 | 2007-03-22 | 流体轴承装置 |
US13/492,467 US8562219B2 (en) | 2006-03-24 | 2012-06-08 | Fluid dynamic bearing device |
Applications Claiming Priority (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006-083457 | 2006-03-24 | ||
JP2006083457A JP4937619B2 (ja) | 2006-03-24 | 2006-03-24 | 動圧軸受装置 |
JP2006083470A JP2007255654A (ja) | 2006-03-24 | 2006-03-24 | 動圧軸受装置 |
JP2006-083470 | 2006-03-24 | ||
JP2006102265A JP2007278326A (ja) | 2006-04-03 | 2006-04-03 | 動圧軸受装置 |
JP2006-102265 | 2006-04-03 | ||
JP2006-156309 | 2006-06-05 | ||
JP2006156309A JP5058516B2 (ja) | 2006-06-05 | 2006-06-05 | 流体軸受装置 |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/293,953 A-371-Of-International US8215843B2 (en) | 2006-03-24 | 2007-03-22 | Fluid dynamic bearing device |
US13/492,467 Continuation US8562219B2 (en) | 2006-03-24 | 2012-06-08 | Fluid dynamic bearing device |
Publications (1)
Publication Number | Publication Date |
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WO2007111218A1 true WO2007111218A1 (ja) | 2007-10-04 |
Family
ID=38541138
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2007/055859 WO2007111218A1 (ja) | 2006-03-24 | 2007-03-22 | 流体軸受装置 |
Country Status (4)
Country | Link |
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US (2) | US8215843B2 (ja) |
KR (2) | KR101413550B1 (ja) |
CN (2) | CN101852245B (ja) |
WO (1) | WO2007111218A1 (ja) |
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KR20110081530A (ko) | 2010-01-08 | 2011-07-14 | 삼성전기주식회사 | 스캐너모터 |
US8804269B2 (en) | 2011-12-06 | 2014-08-12 | HGST Netherlands B.V. | Adjusting rotational speed based on ambient temperature in a HDD |
KR101197897B1 (ko) * | 2012-09-14 | 2012-11-05 | 삼성전기주식회사 | 스핀들 모터 및 이를 포함하는 하드 디스크 드라이브 |
CN105009425B (zh) * | 2013-03-25 | 2019-01-04 | Ntn株式会社 | 烧结轴承及其制造方法、以及具有该烧结轴承的振动电机 |
DE102013217261A1 (de) * | 2013-08-29 | 2015-03-05 | Robert Bosch Gmbh | Kompressor |
CN105090090B (zh) * | 2014-05-12 | 2020-11-17 | 台达电子工业股份有限公司 | 风扇及其油封轴承 |
US8973848B2 (en) * | 2014-09-08 | 2015-03-10 | Efc Systems, Inc. | Composite air bearing assembly |
JP6859832B2 (ja) * | 2017-04-27 | 2021-04-14 | 日本電産株式会社 | 流体軸受装置、モータおよびディスク駆動装置 |
CN107482829A (zh) * | 2017-08-28 | 2017-12-15 | 云南靖创液态金属热控技术研发有限公司 | 一种无刷电机的散热结构 |
US9970481B1 (en) | 2017-09-29 | 2018-05-15 | Efc Systems, Inc. | Rotary coating atomizer having vibration damping air bearings |
TWI705190B (zh) * | 2019-08-27 | 2020-09-21 | 建準電機工業股份有限公司 | 軸承系統 |
CN110848271B (zh) * | 2019-11-19 | 2021-02-23 | 张家港Aaa精密制造股份有限公司 | 一种可调控的滑动轴承及调控方法 |
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- 2007-03-22 KR KR1020087024858A patent/KR101413550B1/ko active IP Right Grant
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Also Published As
Publication number | Publication date |
---|---|
US20090285514A1 (en) | 2009-11-19 |
KR20080110619A (ko) | 2008-12-18 |
CN101852245B (zh) | 2013-03-13 |
KR101460573B1 (ko) | 2014-11-20 |
KR101413550B1 (ko) | 2014-07-01 |
CN102537031B (zh) | 2015-04-01 |
US20120243813A1 (en) | 2012-09-27 |
US8215843B2 (en) | 2012-07-10 |
CN102537031A (zh) | 2012-07-04 |
KR20130129306A (ko) | 2013-11-27 |
CN101852245A (zh) | 2010-10-06 |
US8562219B2 (en) | 2013-10-22 |
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