Abstract: A spindle motor structure including a spindle motor installed on a base and having a hydrodynamic bearing supporting a shaft to be capable of rotating using hydrodynamic pressure and a driving source rotating the shaft using an electromagnetic force. A circuit board is installed to face the base and supplies driving power to the driving source. A heater is installed on the circuit board at a position facing the hydrodynamic bearing and heats the hydrodynamic bearing.

Abstract: A hydrodynamic bearing device has high reliability and is suitable for miniaturization through superior heat resistance and by utilizing a dynamic pressure-generating liquid with little loss due to evaporation. The hydrodynamic bearing device has at least one of a shaft structure and a sleeve having a dynamic pressure-generating mechanism. The dynamic pressure-generating liquid present in a gap between the shaft structure and the sleeve has a main component that is ionic liquid.

Abstract: An oil film bearing (1) for roll pins (4), which or whose pin bush (3) that is placed thereon is surrounded by a bearing bush (3) placed in an insert (2). The bearing bush has at least two inner lying hydrostatic pockets (9, 9?), which are arranged, in essence, in a common axial line and which can be supplied with a pressure medium via a check valve (18) and via boreholes (6, 6?) extending inside the bearing bush (5). Throttles (15, 15?) inside the boreholes (6, 6?) ensure an optimal hydrostatic bearing even when the roll pin (4) or the pin bush (3) is in an oblique position inside the bearing bush (5). The aim of the invention is to improve an oil film bearing of the aforementioned type whereby economically assuring the hydrostatic function of the bearing and in which the inspection of the throttles (15, 15?) is possible without further ado.

Abstract: A fluid dynamic bearing device in which leakage of a lubricating oil can be prevented is provided at low costs. A minute amount of an ink is provided on a first outer circumferential surface 8b2 of a bearing member 8 made of a sintered metal and a pore sealing portion 17 consisting of aggregates of a minute amount of the ink is formed to seal a portion of the fluid dynamic bearing device 1 of the bearing member 8 which is exposed to the air.

Abstract: A robust spindle motor is provided having improved shock resistance for fluid containment, as well as enhanced air purging characteristics. In an aspect, axial displacement of relatively rotating components is restricted by utilizing a limiter situated adjacent to a limiter bushing forming an axial limiter gap therebetween. A fluid channel, at least partially diverging, extends from a hydrodynamic bearing to the axial limiter gap, and continues to a region beyond the axial limiter gap. In an aspect, an axially diverging slot is situated adjacent to the axial limiter gap. Power is reduced by reducing viscous drag between relatively rotating components, hydrodynamic bearing length is increased, and higher stiffness of the hydrodynamic bearing is provided. Fluid volume may be increased, thereby offsetting fluid evaporation losses and allowing for the use of lower viscosity lubricants.

Abstract: There is provided an air foil bearing. The air foil bearing comprises a bearing house and a first foil, wherein a first end of the first foil is fixed with respect to the bearing housing and a second end of the first foil is extended along a peripheral surface of a rotating shaft while maintaining a predetermined clearance with respect to the rotating shaft to thereby become a free end. The air foil bearing also comprises a second foil fabricated from a porous metallic material and extended along the first foil between the first foil and the bearing housing.

Abstract: The invention relates to a fluid dynamic bearing system particularly to rotatably support a spindle motor to drive the disk(s) of a hard disk drive. The bearing system comprises a bearing sleeve and a shaft accommodated in a bore in the bearing sleeve and rotatably supported with respect to the bearing sleeve, the surfaces of the bearing sleeve and of the shaft, which face each other and are separated by a bearing gap (3) filled with a bearing fluid, forming at least one first radial bearing region. According to the invention the diameter of the shaft is chosen such that the relationship between the bearing distance, i.e. the distance of the fixing point of the shaft to the first radial bearing region, and the diameter of the shaft is equal to or less than 0.9, and that the diameter of the shaft is preferably 3 mm to 5 mm. This provision causes the resonance frequency of the bearing to shift to a higher, uncritical frequency range.

Abstract: A bearing system having variably grooved radial and thrust bearing with reduced groove angle near bearing entry is described. In an embodiment, the bearing system includes a housing. The bearing system also includes a shaft centrally located in the housing. The bearing system additionally includes a rotor portion that is adapted to be rotated about the shaft and contained within the housing. The bearing further includes a variably angled groove disposed on an internal surface of the bearing system. The variably angled groove reduces ingestion of air in the bearing system during operation of the bearing system.

Abstract: The present invention provides a fluid bearing unit capable of achieving lower torque and lower current consumption in comparison with a conventional bearing unit, and a spindle motor using the same. The present invention employs an ester derived from 1,5-pentanediol having one alkyl side chain and saturated monovalent fatty acid having 5 to 8 carbon atoms as a base oil of a lubricant with which a gap between a shaft and a sleeve is filled.

Abstract: A bearing unit (90) for rotatably supporting a shaft (100) comprises a seamless holding member (120) with a gap allowing a shaft to run through and extend to the outside, a bearing (130) arranged in the inside of the holding member to rotatably support the shaft so as to make it radially revolvable, an anti-shaft-release member (115) fitted to the shaft so as to abut the bearing in order to prevent the shaft from slipping away in the thrusting direction and a space-forming member (113) arranged in the inside of the holding member so as to secure a space around the anti-shaft-release member. A bearing unit may further comprise an lubricating oil seal member and the space-forming member may be used to form a passage way for lubricating oil to prevent lubricating oil from leaking.

Abstract: A bearing component 7 comprises a sleeve 2 having a bearing hole 2a in which a shaft 1 is inserted, a communicating hole 6 formed in the sleeve 2, a lubricant 20 held in the gap between the shaft 1 and the sleeve 2, for example, an inner peripheral seal portion 12 that holds the lubricant 20 in the bearing component 7, and a flow suppressing wall 30 formed between the communicating hole 6 and the inner peripheral seal portion 12. The flow suppressing wall 30 impedes the flow of the lubricant 20 toward the inner peripheral seal portion 12, and disperses it in the circumferential direction.

Abstract: A fluid dynamic bearing mechanism that can ensure bearing rigidity, reduce shaft loss torque, reduce power consumption, stabilize axial rotation, and improve rotational accuracy is disclosed. The fluid dynamic bearing mechanism being suitable for use in a hard disk drive. In the fluid dynamic bearing mechanism (equipped with a bearing case, endplate, and shaft) a cylindrical hole of the bearing case is changed to a stepped cylindrical hole that has a large diameter part and a small diameter part. The shaft is changed to a stepped shaft that has a large diameter part and a small diameter part. On the outer circumference of either the large diameter part of the stepped cylindrical hole, or the large diameter part of the stepped shaft, a first dynamic pressure groove is be formed. On the outer circumference of either the small diameter part of the stopped cylindrical hole or the small diameter part of the stepped shaft, a second dynamic pressure groove is being formed.

Abstract: A fluid dynamic bearing assembly includes a bearing sleeve (30) having an inner surface and a rotary shaft (30) rotatably received in the bearing sleeve. The rotary shaft has an outer surface. One of the inner surface of the bearing sleeve and the outer surface of the rotary shaft forms a dynamic pressure generating groove pattern (10). The groove pattern includes a plurality of grooves (12) extending from a center area toward one edge of the groove pattern. Each of the grooves has at least one of a depth and a width decreasing from the center area toward the edge.

Abstract: Disclosed is a drum washing machine having ball balancers for rapidly reducing the vibration of a drum. The drum washing machine includes a drum rotatably installed so as to wash or dehydrate laundry; and balancers, each including a plurality of masses; a housing provided with a race having a rectangular section, on which the masses move in a circumferential direction; and a fluid filling the inside of the race for reducing noise caused by the circumferential movement of the masses. The race has a rectangular section, corner portions of which are rounded, and a value obtained by dividing the radius of the corner portions by the radius of the masses is between 0.4 and 0.9 so as to effectively reduce the vibration of the drum. The drum washing machine effectively reduces the vibration of the drum while using a small amount of the fluid.

Abstract: A hydrodynamic bearing device which can improve workability of injecting a lube repellant and effectively prevent leakage of a lubricant, a method for manufacturing the same, a spindle motor, and a recording and reproduction apparatus are provided. A hydrodynamic bearing device 4 includes a lube repellant 11a which is applied in a circular shape by a predetermined distance in a radial direction from a portion of an upper surface of a second thrust flange 41c where it is connected to a shaft 41 and a lube repellant 11b which is applied in a circular shape on an outer peripheral surface of the second thrust flange 41c below from an upper end in the radial direction by a predetermined distance. The lube repellant 11b is applied near the upper end portion in a gap formed between the outer peripheral surface of the second thrust flange 41c and an inner peripheral surface of an outer sleeve 44.

Abstract: A resin housing 7 is injection-molded by using a forming mold 11. Moreover, a concave shaped adhesive reservoir 10 is formed by a sink mark of the resin during injection molding on its inner circumferential surface 7e simultaneously with the injection molding of the housing 7. Accordingly, the adhesive can be prevented from overflowing and the adverse influence caused by the overflowing of the excessive adhesive can be avoided. A decrease in the molding precision of the housing can be also prevented and cost reduction by dispensing with a processing step can be enabled.

Abstract: There is disclosed a radial piston machine comprising a cylinder block having at least one bore in which a piston supported on an eccentric disk is movably guided via roll bodies, wherein at least one hydrostatic relieving field is provided between the piston and the roll body. According to the invention, the active surface A2 of the relieving field is equal to or larger than the active piston area A1 of the piston restricting a cylinder chamber and the relieving field is in fluid communication with the cylinder chamber via a hydraulic resistance.

Abstract: For a motor having fluid dynamic bearing(s) defined by surfaces of relatively rotatable motor members, aspects include providing a capillary reservoir between relatively irrotatable surfaces. The capillary reservoir may comprise a tapering gap that is vented to a gaseous environment through one end of the gap and is in fluidic communication with the fluid dynamic bearing(s) through another end of the gap. The gap may be axial, and the capillary reservoir may be disposed coaxially with one or more of the fluid dynamic bearing(s) about an axis of rotation. The capillary reservoir may extend from proximate a top portion of the motor to proximate a bottom portion of the motor.

Abstract: A fluid dynamic bearing system having at least one stationary part and one rotating part that form a bearing gap filled with bearing fluid between the opposing bearing surfaces, at least one end of the bearing gap being open and sealed against the environment by a sealing means, pumping grooves being provided on at least two spatially separated bearing surfaces to generate hydrodynamic pressure and at least one supply volume connected to the bearing gap being available for the bearing fluid. The distinctive feature of the invention is that the sealing means are formed by pumping grooves that are disposed at the open and of the bearing gap on at least one of the bearing parts and designed in such away that they generate a pumping action on the bearing fluid directed towards the interior of the bearing and, as a result, create a dynamic seal for the open end of the bearing. The bearing system itself is designed as a compact unit preferably consisting of only three parts.

Abstract: In a method for manufacturing a bearing member which is made of a porous material and has dynamic pressure grooves formed by electrochemical machining, the bearing member is impregnated with liquid such as hydrosoluble liquid or water prior to electrochemical machining. Since the hydrosoluble liquid or water is retained due to capillary force in the bearing member for which electrochemical machining is to be performed, the hydrosoluble liquid or water is not replaced with an electrolyte used in the electrochemical machining. Thus, the step of removing the electrolyte after electrochemical machining can be omitted, increasing production efficiency. Moreover, the bearing member is free from a trouble of rust as the electrolyte does not remain in the bearing member. Since the hydrosoluble liquid or water exhibits excellent affinity for the electrolyte, it does not harm processing accuracy in electrochemical machining and can be easily removed after electrochemical machining.

Abstract: A gas bearing spindle (2) for use in processing apparatus (1), for example ion implantation apparatus. The spindle (2) has a steel bearing surface (23) and a shaft (3) coated with chrome (3a) or another hard material.

Abstract: A hydrostatic bearing design employing inherently compensated orifices whose geometric design is such that the use of multiple orifices is substantially simplified. In normal cylindrical hydrostatic bearings, the orifices are usually employed in rows. There can be from three to 120 orifices per row, and usually from one to six rows in most designs. In these designs, the orifice is usually a separate component, which is pressed into the surface that constitutes the bearing. Inherently compensated orifices are comprised of three sections, i.e. the entrance section, the restricting orifice section, and the exit section. The first two of these sections are of circular cross section. This design employs slots versus cylindrical type of construction, thereby giving square or rectangular cross sections. The manufacturing of this type of hydrostatic bearing is greatly simplified since only three or slightly more parts are required, versus a separate part for each orifice.

Abstract: A rolling bearing has a first ring, a second ring concentric with the first ring, and a plurality of rolling elements disposed between the first and second rings, the first ring and the second ring both being generally annular and having gaps therein. A rotating mechanism has a support structure, a rotating structure, and a rolling bearing as described herein mounted on the support structure and engaging the rotating structure. A rotating mechanism having a CTE and a non-split ring bearing having a bearing CTE that is significantly less than the mechanism CTE can be improved by replacing the non-split ring bearing with a bearing having a similar CTE and a gap in the inner ring and in the outer ring.

Abstract: The present invention provides a process for producing a saturated aliphatic hydrocarbon prepared using an ?-olefin as a raw material and represented by the general formula (1), including the steps of: (I) producing a vinylidene olefin by dimerizing the ?-olefin in the presence of a metallocene complex catalyst; (II) further dimerizing the vinylidene olefin in the presence of an acid catalyst; and (III) hydrogenating the obtained dimer. Further, there are provided a lubricant composition containing the saturated aliphatic hydrocarbon compound produced by the above process, a bearing oil consisting of the lubricant composition, and making use of the same, a bearing and gyral equipment. The saturated aliphatic hydrocarbon compounds produced by the process of the present invention have low-temperature fluidity, exhibiting low evaporativity, and excellent in thermal stability and oxidation stability.

Abstract: The invention relates to a hydrodynamic bearing arrangement for an electric motor, particularly for a spindle motor to drive the platters of a hard disk drive. The bearing arrangement comprises a shaft, a bearing bush and a thrust plate disposed fixedly on the shaft, the shaft and the thrust plate rotating with respect to the bearing bush, grooved patterns to generate fluid-dynamic pressure being provided on the thrust plate and/or the surfaces located opposite the thrust plate of the bearing sleeve and/or the cover plate. The grooved pattern comprises a number g of grooves distributed over the surface of the bearing sleeve, the thrust plate or the cover plate, wherein in the shaft and/or in the thrust plate, a number h of holes and/or recesses are provided at the inner edge of the thrust plate and/or at the outer edge of the shaft. According to the invention, the number g of grooves cannot be integrally divided by the number h of holes and likewise that h cannot be integrally divided by g.

Abstract: A fluid dynamic-pressure bearing includes a thrust dynamic-pressure bearing between a bearing member and a rotor hub and a tapered sealing portion continuous with the thrust dynamic-pressure bearing and defining a radial gap whose width gradually increases in the axial direction. A neck is formed in a passageway between the thrust dynamic-pressure bearing and a lubricating fluid/air interface maintained in the tapered sealing portion for increasing flow resistance of the lubricating fluid.

Abstract: A shaft is rotatably inserted through a bearing hole of a sleeve, a screw hole for fastening a clamp to the shaft is formed along a direction of an axis from an upper end portion of the shaft, an operating fluid is charged in a gap between an inner peripheral surface of the sleeve and an outer peripheral surface of the shaft, and radial bearing parts constituted of dynamic pressure generating grooves are provided on the inner peripheral surface of the sleeve. As for an inside diameter of the sleeve, an inside diameter in a predetermined range from the opening upper end part is formed to be larger by an expected deformation amount in a diameter direction of the shaft than an inside diameter in a range at a lower end side from the predetermined range. The predetermined range corresponds to a range including a radial bearing part located at the upper end side.

Abstract: A method for filling the bearing gap of a hydrodynamic bearing with a lubricant, where drops of lubricant are produced in a defined manner and are applied to a defined region of the bearing to be filled.

Abstract: A servo track writer assembly and method are provided for recording servo pattern information on a disc. The servo track writer assembly includes a spindle assembly, an actuator assembly and a servo recording head. The spindle assembly has a hub, which supports the disc and a spindle motor for rotating the hub. The actuator assembly has an actuator arm supported by an actuator bearing for positioning the actuator arm relative to the disc. At least one of the spindle motor and the actuator bearing has a gas-lubricated bearing with a working fluid, which includes helium. The servo recording head is supported by the actuator arm relative to the disc to record the servo pattern information on the disc as the spindle motor rotates the disc and the actuator bearing positions the actuator arm.

Abstract: A method of lubricating a wave bearing comprising application of an oil comprising a perfluoropolyether, derivatized perfluoropolyether, fluorosilicone, polychlorotrifluoroether, or polyphenyl ether, wherein the oil is capable of sustaining temperatures greater than 121° C., and at an operating speed of up to 1.4 million DN without decomposition.

Abstract: Method and arrangement for oscillation isolation by means of an air bearing. The electropneumatic valves (4) for the compressed-air supply to the air bearing are subjected to a dither signal. This causes additional vibration of the mass 1 to be isolated. A compensation signal transmitter (12) ensures that additional vibration of the mass (1) is suppressed, by controlling actuators (10). Overall, hysteresis effects are avoided in the control of the compressed-air flow.

Abstract: At least one of a shaft and a bearing of a fluid dynamic bearing unit includes an additive-providing portion including the additive on a surface thereof. The lubricating oil is retained between the shaft and the bearing, and contacts the surface of the additive-providing portion. The additive-providing portion is for example a joining member such as adhesive, a housing made of resin, a sleeve made of porous material, an oil repellent coating made of oil repellent agent, and a lubricating coating.

Abstract: A bearing positioning structure for a motor includes an axial tube and a positioning member. The positioning member includes a pressing portion and a coupling portion. The coupling portion of the positioning member is engaged with a coupling section of the axial tube for securely mounting the positioning member to the axial tube, with the pressing portion of the positioning member pressing against a bearing to position the bearing in the axial tube. In another example, the coupling portion of the positioning member engages with a coupling section on a stator.

Abstract: Herein disclosed a bearing unit including: a dynamic pressure fluid bearing adapted to receive a rotary shaft inserted thereinto; a unit main body surrounding the outside of the fluid bearing; a lid member covering an upper opening of the unit main body with the rotary shaft inserted into the dynamic fluid bearing; lubricating oil poured into the unit main body; and an oil thrower ring rotating together with the rotary shaft in a space defined between an upper end of the fluid bearing and the lid member; wherein a gap defined between the lid member and the oil thrower ring is tapered in cross-section so as to be progressively reduced in the distance therebetween as the gap is spaced apart from the center of the rotary shaft.

Abstract: A system and method for improving lubrication in a fluid dynamic bearing are disclosed. A fluid dynamic bearing comprising a rotor portion and a stator portion is formed. In addition, a lubricating fluid comprising a high pressure lubricant is provided between the rotor portion and the stator portion of the fluid dynamic bearing, wherein the high pressure lubricant provides extreme pressure protection of the rotor portion and the stator portion of the fluid dynamic bearing.

Abstract: A workholder comprising a body comprising a fluid bearing and a fluid, wherein the fluid bearing is adapted to releasably retain a workpiece by maintaining the fluid in a gap between the workholder and the workpiece, wherein the fluid bearing is adapted to produce a radial and/or an axial force on the workpiece, and wherein the workholder does not include a mechanical interface to releasably retain the workpiece is disclosed. Also, methods of using and manufacturing the workholder are disclosed herein.

Abstract: A fluid bearing that utilizes a variable depth groove is described. The fluid bearing includes two surfaces that are rotatable relative to one another, with a groove on at least one of the surfaces. The floor of the groove is non-constant in depth.

Abstract: Disclosed is an aerodynamic bearing assembly for a spindle motor for hard disk drives, in which a hub of the spindle motor is pivoted in both radial and thrust directions by the ball bearing, which directly contacts the center of the hub, to perform rotation according to the rotational principle of a whirligig, and is subject to the thrust load through the aerodynamic bearing assembly with air groove(s) without being in contact with it, so that the hub maintains a rotational center without mechanical contact resulting in noise and starting failure of the assembly during an initial starting (low-speed rotation). The assembly includes air grooves, the air groove generating aerodynamic pressure between the hub and the aerodynamic bearing while the hub rotates.

Abstract: A fluid dynamic bearing assembly including a shaft and a bearing sleeve. A bearing gap is formed between the shaft and the bearing sleeve and is filled with a lubricating fluid. A capillary seal is formed at one end of the bearing sleeve, and a recess is formed in the shaft immediately above the capillary seal. The surface of the recess forms an acute angle with an axis of the shaft.

Abstract: A spindle motor having a hydrodynamic pressure bearing includes a stator, a rotor, and a dynamic pressure generating unit including a sleeve having an upper plate disposed opposite to the rotor and at least one thrust dynamic pressure groove formed either at the upper plate of the sleeve or at the rotor. Inside width from a neutral radius to an innermost radius of the thrust dynamic pressure groove is larger than outside width from the neutral radius to an outermost radius of the thrust dynamic pressure groove such that the neutral radius is biased to the outside of the thrust dynamic pressure groove. Dynamic pressure at the inside width of the thrust dynamic pressure groove is higher than dynamic pressure at the outside width of the thrust dynamic pressure groove such that fluid supplied into the thrust dynamic pressure groove is guided to the outer diameter side.

Abstract: An object of the present invention to provide a hydrodynamic bearing device and a motor having a high performance and reliability which prevents deterioration in a temperature property due to a difference in coefficients of linear expansion of a sleeve and a shaft and prevents abrasion of bearing surfaces of both the sleeve and the shaft. The sleeve is formed of a copper metal material or an iron metal material and is treated with electroless nickel plating at least on the surface which opposes the shaft. The shaft includes 0.2% by weight C, 0.3% by weight Si, 8% by weight Mn, 0.2% by weight S, 2.5% by weight Ni, and 14% by weight Cr, and a main component of the shaft is a manganese alloy steel including Fe.

Abstract: A gas bearing system comprising two opposing substantially parallel bearing surfaces (2, 3) and at least one gas duct (6) for supplying gas through an orifice (7) to the bearing gap (5) between the bearing surfaces (2, 3). At least one of the bearing surfaces (2, 3) is provided with at least one cavity (8, 9) extending over 0.3 mm2 to 3 mm2 of the at least one bearing surface (2, 3). The content of the cavity (8, 9) may be between 0.3 mm3 and 4 mm3. The gas duct (6) may supply gas to the cavity (8) through an orifice (7) in the wall of the cavity (8).

Abstract: There is provided a spindle device utilizing an externally pressurized gas bearing assembly, in which the center of a pulse disc of a rotary encoder can be adjusted to minimize an unbalance of the weight of the pulse disc and such unbalance can be adjusted easily to minimize fluctuation of the pulse disc during rotation and to achieve a highly precise detection of the rotational position consistent with the resolution of the rotary encoder. The spindle device includes an externally pressurized gas bearing assembly (3) for rotatably supporting a shaft (1), a motor (10) for driving the shaft (1), and a rotary encoder (19) for detecting a rotational position. A pulse disc (16) of the rotary encoder (19) is fixed on a mounting surface (S), arranged in the vicinity of one end of the shaft (1) and lying perpendicular to a central axis of the shaft (1), by a fastening member (17) such as a bolt removably inserted through a fastening member inserting portion (7) provided in the pulse disc (16).

Abstract: The invention relates to a fluid dynamic bearing system particularly for a spindle motor having a rotating component comprising a shaft and a hub connected to the shaft, and a stationary component comprising a bearing bush made of a porous material, the shaft being accommodated in the bearing bush and rotatably supported with respect to the bearing bush, and there being a bearing gap filled with a bearing fluid between the shaft and the bearing bush. According to the invention, the bearing bush is at least partly enclosed by a sleeve, a surface of the sleeve together with an adjoining surface of the rotating component forming a conical seal.

Abstract: Disclosed herein is a hydrodynamic bearing which has improved ability to efficiently seal fluid (lubricant), which generates dynamic pressure. The hydrodynamic bearing provides a fluid storage space that couples a fluid reservoir with a hydrodynamic space, in addition to a fluid reservoir defined by a spacer and a cover. The fluid storage space has a cross-section that gradually tapers in a fluid supply direction, thus serving as an additional fluid reservoir for sealing fluid and supplying the fluid to the hydrodynamic space, when necessary. Further, unlike the prior art, where a fluid surface is controlled in a relatively narrow fluid reservoir, the fluid surface can be controlled in a relatively wide fluid storage space, and air bubbles generated in the hydrodynamic space can be easily discharged to the outside, thus affording convenience when the hydrodynamic bearing is used.

Abstract: An object of the present invention is to provide a hydrodynamic bearing type rotary device which can improve rotation performance, suppress a friction torque, and reduce power consumption of motor, and a recording and reproducing apparatus including the same. A shaft having a flange on one end and a hub on the other end is provided with a bearing of a sleeve so as to be rotatable. The sleeve includes a communication hole. A third gap between the hub and the sleeve end surface is a flow path, and is connected to the communication hole. Provided that a first gap between a thrust plate 4 and the flange 3 is S1, a second gap between the flange 3 and a lower end surface of the sleeve 1 is S2, and a third gap between the upper end surface of the sleeve 1 and the hub 7 is S3, widths of the gaps satisfy the relational expression, S3>(S1+S2).

Abstract: A bearing structure which is cooperated with a shaft and is disposed in a bearing tube comprises an oil bearing and a cylindrical sealing member. The oil bearing has an axial hole. The shaft passes through the axial hole. The cylindrical sealing member covers a top surface and at least a portion of a sidewall of the oil bearing. The cylindrical sealing member has a through hole defined in its center. The shaft passes through the through hole.

Abstract: The bearing unit of the present invention has: a shaft; a radial bearing which supports the shaft in a circumferential direction of the shaft; a thrust bearing which supports an end of the shaft in a thrust direction of the shaft; a housing having a closed structure except for a shaft insertion hole in which the shaft is inserted, with the radial bearing and the thrust bearing being provided inside the housing; a stopper member which prevents the shaft from being pulled out of the radial bearing; and viscous liquid filled in the housing. The stopper member is made of an elastic member which is elastically deformed only in the radial direction and is hardly deformed in the axial direction. Hence, the shaft is prevented from being pulled out from the housing, and shortage of the lubrication oil around bearing surfaces is prevented from being caused by lifting of the shaft.

Abstract: The invention relates to a spindle motor having a fluid dynamic bearing system used particularly for driving the storage disks of hard disk drives, having a baseplate, a stationary bearing bush disposed in an opening in the baseplate, a shaft rotatably supported in an axial bore in the bearing bush by means of the fluid dynamic bearing system, a hub connected to the shaft, and an electromagnetic drive system. In order to increase the stiffness of the motor system, according to the invention the bearing bush is provided with a flange that is fixed in the opening in the baseplate and whose outside diameter is distinctly larger than the outside diameter of the bearing bush. Instead of a flange at the outer diameter of the bearing bush there can be provided a sleeve at the base plate which receives the bearing bush at least partly.

Abstract: In a method of manufacturing a shaft for the fluid dynamic bearing device, the shaft is formed with a plurality of grooves arranged in and around the external circumference, the surface of the grooves and external circumference with uniform roughness, and machined marks on the surface aligned in the circumferential direction, by controlling the relative vibration of a rod-shaped blank to be machined as the shaft for a fluid dynamic bearing and a grinding wheel (a machining tool) to grind the external circumference of the blank.