Abstract: A fluid dynamic pressure bearing device includes a shaft member (5) and a bearing member (41), at least one of the shaft member or the bearing member being rotatable with respect to the other. A shaft member-side annular member (13) is fixed with respect to the shaft member. The shaft member-side annular member includes a large-diameter rim portion and a small-diameter outer circumferential surface portion. A bearing member-side annular member (14) is fixed with respect to the bearing member. The bearing member-side annular member includes an inner circumferential large-diameter step portion, and a small-diameter inner circumferential surface portion.

Abstract: A bearing assembly for use in an electric motor minimizes the generation of a negative pressure. In the bearing assembly, gaps are formed between a shaft provided with a flange portion, a ring member mounted on the shaft, and a sleeve member with a through hole formed therein are continuously filled with lubrication oil. When a rotor rotates, the rotor is supported by a fluid dynamic pressure. In the bearing assembly, herringbone grooves are formed in an upper surface of the flange portion of the shaft fixed to a base plate. When the sleeve member rotates with respect to the shaft, ends of all of the herringbone grooves and the through hole are superposed on each other sequentially. Thus, the lubrication oil can be efficiently supplied to an outer peripheral region in the thrust dynamic pressure bearing mechanism in which the negative pressure is most prone to be generated, and generation of the negative pressure can be efficiently minimized.

Abstract: A fluid dynamic bearing mechanism for a motor (1) suitable for use in a hard disk drive and having a compact and thin shape, high bearing rigidity, and high rotating accuracy, and which securely keeps the rotor member (6) in place against shocks, and allows the inspection of lubricant supply amount easily. A fluid dynamic bearing mechanism having a capillary seal part (12) on one end of lubricant supply part formed by a minute gap including dynamic pressure grooves (10) formed on a shaft member (5) or a bearing member (4) is provided. An annular member (13) is fitted on the shaft member at the location corresponding to the capillary seal part, another annular member (14) is fitted on the bearing member at the location corresponding to the capillary seal part, a taper or step (13a, 14a) is formed on the outer peripheral surface of the annular member on the shaft member side and the inner peripheral surface of the annular member on the bearing member side.

Abstract: In spindle motors journaled on fluid-dynamic-pressure bearings, especially in such spindle motors employed in recording-disk drives in implementations that subject the drives to vibration and shock, sealing performance of a capillary seal formed between motor rotor-side and stator-side bearing surfaces, cohesiveness of oil-repellant on rotor-side/stator-side dry-area surfaces adjoining the capillary seal section, and motor inter-component adhesive strength are improved. The capillary-seal-constituting rotor-side/stator-side surface(s) are exposed to a plasma or to ultraviolet rays under predetermined conditions to improve the wettability of the surface(s) for the bearing fluid. The dry-area surface(s) are similarly irradiated so as to improve their wettability for the oil-repellant. Adhesively bonded component surfaces are likewise irradiated so as to improve their wettability for the adhesive, enhancing adhesive strength.

Abstract: A hydrodynamic bearing device which realizes power saving, reduction of a time period necessary for stabilizing rotation, and enhancement in durability to startup and halting of the motor at the same time by accelerating circulation of a lubricant in the vicinity of a flange with torque loss being kept low is provided. A flange (3) is fixed to one end of a shaft (2). On an inner surface of one of openings of a sleeve (1), a step portion (1C) is provided. When the shaft (2) is inserted into the sleeve (1), the flange (3) is in close vicinity to the step portion (1C). An inner diameter of the step portion (1C) is smaller in end portions in an axial direction than in a central portion. Thus, a gap between an outer surface (3C) of the flange (3) and a surface of the step portion (1C) which opposes the outer surface (3C) is narrow in the vicinity of boundaries of the outer surface (3C) of the flange (3) than in the vicinity the central portion.

Abstract: Fixation strength of a bearing sleeve with respect to a housing is increased so that stable bearing performance can be achieved. A fluid dynamic bearing device (1) includes a housing (7) and a bearing sleeve (8) fixed to an inner periphery of the housing (7). The housing (7) and the bearing sleeve (8) have therebetween a press-fitting part (10) at which the housing (7) and the bearing sleeve (8) are fixed by press-fitting, and an adhesive-filled part (11) formed on an opening side with respect to the press-fitting part (10).

Abstract: In a rotor hub manufacturing method, a workpiece is chucked and a hole centering on the workpiece center axis is formed in the workpiece. A sealing member is press-fit into the hole, forming an internal space. A shaft feature is thereafter shaped in the workpiece by cutting work done on the periphery of the workpiece around the hole. The workpiece part including the shaft feature is then cut away from the workpiece to form a rotor hub as a shaft unit.

Abstract: An apparatus and method are described for a fluid dynamic bearing motor as may be utilized in a disc drive memory system. A fluid seal is situated at a first axial end of a bearing, and a grooved pumping seal is situated at a second axial end of the bearing. In an aspect, a fluid recirculation passageway is defined through a shaft and a thrustplate, to recirculate fluid from axially above the grooved pumping seal at the second axial end of the bearing to the first axial end of the bearing. Any air ingested at the grooved pumping seal, or which came out of solution from the fluid, is purged into a fluid reservoir and out the fluid seal. In an aspect, fluid is recirculated from the center of the journal bearing and the bearing pressure grooves to the fluid recirculation passageway and toward an air purging fluid seal.

Abstract: A system and method are provided for reduced power consumption and reduced wear in a spindle motor. The spindle motor includes a fluid dynamic bearing containing gas defined between a stationary component and a rotatable component. A liquid layer is coated on at least a portion of at least one of the rotatable component surface and the stationary component surface. The liquid layer is formed from a liquid having a predetermined concentration, and formed having a predetermined thickness. The predetermined thickness is accomplished utilizing at least one of a predetermined dwell time, withdraw velocity and bearing surface roughness. In an aspect, the liquid layer is formed with an increased thickness by at least one of increasing the liquid concentration, increasing the dwell time, and increasing the withdraw velocity. In an aspect, a method is provided to obtain thin liquid film thicknesses ranging from about 5 nm to about 350 nm.

Abstract: A hub portion of a fluid dynamic bearing device is formed from a resin composition in which polyphenylene sulfide (PPS) is employed as a base resin and with which carbon fibers are mixed. In this manner, the wear resistance and the conductivity can be improved. Alternatively, both portions of a stationary body and a rotating body of the fluid dynamic bearing device which portions face to each other through a bearing gap are formed from a resin composition in which polyphenylene sulfide (PPS) is employed as the base resin. In this manner, excellent wear resistance can be obtained.

Abstract: A fluid dynamic pressure bearing composed of a cylindrical sintered compact includes: a thrust region which is formed on an end surface of the bearing and receives at least a thrust load; a roughed portion having small peaks and valleys formed on the thrust region; and thrust recesses for generating thrust fluid dynamic pressure, which are formed on the thrust region.

Abstract: A hydrodynamic bearing device including a sleeve (1), a shaft (2), and oil (100). With respect to the sleeve (1), a stepped portion (1b) provided at one end and an inner peripheral face (1e) extending linearly in the axial direction and continuously with the stepped portion (1b) are formed by a working method that involves the use of a metal mold. The shaft (2) is inserted so as to be capable of relative rotation with respect to the inner peripheral face (1e) of the sleeve (1). The oil fills the space formed between the inner peripheral face of the sleeve and the outer peripheral face of the shaft. Dynamic pressure generation grooves (9a and 9b), which open in the axial direction at at least one end in the axial direction of the inner peripheral face (1e) and are continuous in the axial direction from one end, are formed in the inner peripheral face.

Abstract: While applying an ultrasonic vibration to a housing 7 and/or a bearing sleeve 8, the outer peripheral surface 8d of the bearing sleeve 8 is press-fitted into the inner peripheral surface 7c of the housing 7 with a predetermined interference, and is welded thereto. During the press-fitting, the region of the inner peripheral surface 7c of the housing 7 coming into contact with the bearing sleeve 8 is melted or softened by the action of the ultrasonic vibration, so that, as compared with a case in which only press-fitting is conducted, the requisite press-fitting force at the time of press-fitting can be substantially reduced.

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: A fluid dynamic bearing includes a bearing member (30) axially defining an inner bearing hole therein, and a spindle shaft (20) rotatably received in the bearing hole with a bearing clearance formed between an inner periphery of the bearing member and an outer periphery of the spindle shaft. Lubricant is filled in the bearing clearance. One of the inner periphery and the outer periphery comprises a bearing surface (10) with channels formed therein. The channels form a plurality of outer communication ends (1316b) at opposite sides of the bearing surface in the axial direction of the bearing member.

Abstract: A hydrodynamic bearing device being low in torque, low in power consumption, high in reliability and best suited for miniaturization and a spindle motor using the same. The hydrodynamic bearing device in accordance with the present invention, dynamic pressure generation grooves being provided on at least one of a shaft or a sleeve, and a lubricant being present in a clearance where the above-mentioned shaft and the above-mentioned sleeve are opposed to each other, is characterized in that the above-mentioned lubricant contains diesters obtained from a divalent alcohol having 4 to 8 carbon atoms and having no alkyl side chain at the ? position and one or more kinds of saturated monovalent fatty acids having 9 to 13 carbon atoms.

Abstract: A rotary gas bearing is described that comprises a first part rotatable relative to a second part. The first part comprises a support member and a first portion and a second portion attached to the support member. The first portion comprises a first bearing surface and the second portion comprising a second bearing surface. Both the first portion and the second portion are attached to the support member by screw thread connections. The second part may comprise complimentary bearing surfaces. Epoxy may be used to fix the first and/or second portions to the support member. A method of determining the bearing working gap by measuring gas flow through the bearing is also described.

Abstract: In a fluid dynamic pressure bearing device using ionic liquid as lubricant, a shaft member and a sleeve member are not corroded by the ionic liquid and static electricity generated is not accumulated. Aluminum with an oxide film formed on its surface is used as the material of the shaft member 11 and the sleeve member 12 and aluminum exposure portions B1, B2 are provided on the surfaces making contact with the ionic liquid, other than dynamic pressure generating grooves, of the shaft member 11 and the sleeve member 12. Accordingly, the shaft member 11 and the sleeve member 12 are kept substantially in the same electric potential through the ionic liquid.

Abstract: A bearing unit wherein a radial bearing for bearing a shaft in the circumferential direction of the shaft and a metallic housing provided with an attaching section are integrated with each other by molding, a resin molded body formed by the molding is so formed as to sealingly contain the radial bearing therein and is provided on one end side in the axial direction thereof with a shaft passing hole through which to pass the shaft, and the inside of the resin molded body is filled with a viscous fluid, whereby the viscous fluid such as a lubricating oil can be prevented from leaking, and the bearing unit can be attached to an object easily and assuredly.

Abstract: A fluid dynamic bearing with an immiscible fluid barrier deposited on the bearing oil is disclosed. One embodiment provides the fluid dynamic bearing having a seal gap to define a seal cavity. The seal cavity is filled with the bearing oil for lubricating the fluid dynamic bearing. The immiscible fluid is disposed on the bearing oil to prevent the bearing oil from evaporating from the seal cavity. In one embodiment, the immiscible fluid is insoluble in the bearing oil.

Abstract: The invention relates to a motor lubricant cycling system, wherein a plurality of slots are disposed in the inner wall of the shaft tube in contact with the bearing, one end of the slot is connected to the conjunction of the top side of the bearing and the shaft, the lubricant, due to the pump effect, elevates along the shaft when the motor is rotating at high speed and is sucked in the slot by a backflow suction, and the other end of the slot is connected to the lubricant container beneath the bearing in formation of a guiding path dedicated to the lubricant cycling. According, the lubricant can be recycled for operation so as to reduce the noise resulting from the motor operation and prolong the life cycle.

Abstract: A tapered roller bearing for a pinion shaft according to the invention includes an inner ring that has an outer circumferential surface on which an inner ring raceway surface is formed and that is integrally fixed to a one-end-side of the pinion shaft, an outer ring that has an inner circumferential surface on which an outer ring raceway surface is formed and that is fixed to a housing, and a plurality of tapered rollers rollably interposed between both of the raceway surfaces. An annular oil reservoir groove for storing lubricating oil is formed in a distal end portion at the one-end-side in an axial direction of the inner circumferential surface by being recessed thereinto adjacent to the outer ring raceway surface.

Abstract: A bearing includes a hub to drive recording media; a sleeve to rotatably support the hub to define a hydrodynamic pressure generating space between the hub and the sleeve, the sleeve being formed with a fluid outlet through which the fluid passes at the predetermined position; a plurality of recesses to generate hydrodynamic pressure, the recesses being formed on at least one of the hub and the sleeve to be opened toward the hydrodynamic pressure generating space; and a fluid circulating member to circulate the fluid out-flowing from the fluid outlet to the hydrodynamic pressure generating space, the member being fixedly combined with the hub to slidably support the sleeve.

Abstract: A fluid dynamic pressure bearing includes a shaft arranged along a central axis, an annular member fixed to the shaft, a sleeve, a lubricant, and a lubricating film. A stepped surface is provided on the outer circumferential surface of the shaft. The annular member preferably includes a lower surface extending radially with respect to the central axis and arranged to make contact with the stepped surface in the inner edge portion of the lower surface. The sleeve preferably includes an upper surface axially opposed to the lower surface of the annular member. The lubricant is provided between the shaft and the sleeve and between the annular member and the sleeve. The lubricating film is provided on the lower surface of the annular member at least over a region lying radially outwardly of the inner edge portion of the lower surface.

Abstract: An inner space of a housing sealed with a seal member as well as internal pores of a bearing member (pores in a porous structure) are filled with a lubricating oil without the presence of air, so that the oil surface of the lubricating oil is within a seal space. Under a reduced pressure of 100 Torr, no lubricating oil leaks outside of the housing even at any attitude of the fluid lubricated bearing device such as normal, inverted, or horizontal attitude.

Abstract: A method of making a fluid dynamic bearing (10) includes the flowing steps. At least two bearing parts (10a, 10b) are firstly provided. Each of the bearing parts has its shape corresponding to a portion of the fluid dynamic bearing to be formed. Then, the bearing parts are combined to form a profile of the fluid dynamic bearing to be formed. Finally, the combined bearing parts are sintered to form an integral body. The fluid dynamic bearing is thus obtained.

Abstract: An active thrust management system varies pressure responsive to changes in rotor assembly thrust to maintain a desired position. The system includes a bearing supporting rotation of a rotor assembly within a pressurizing chamber. The rotor assembly is supported on a cushion of air generated between the bearing and the rotor assembly. Pressure within a cavity adjacent the rotor assembly opposes a thrust force to maintain a desired position of the rotor assembly. Modulating airflow into the pressurizing chamber adjacent the rotor assembly compensates for changes in the thrust generated by the rotor assembly to maintain the desired rotor assembly position.

Abstract: A fluid dynamic bearing device is mainly composed of a housing, a bearing sleeve, and a rotary member. The housing is formed by a side portion formed through injection molding of a resin material, and a bottom member fixed to a fixing portion provided in the inner periphery at one axial end of the side portion and adapted to close an opening at one axial end of the side portion. The fixing portion is a molding surface formed through solidification, in conformity with the inner surface of the mold, of the resin injected by the injection molding.

Abstract: A fluid bearing includes hydrostatic pads formed in a surface and positioned to exert a separating force, and a land formed on the surface of the insert and configured to act as a bushing to allow rotation while the first and second pads are pressurized at less than a hydrostatic balance force. Pressurized fluid to the pads of the insert is controlled to prevent operation in full hydrostatic mode. More particularly, a separating force generated by surface force of the pads is controlled such that the separating force does not exceed a force exerted on the bearing. The fluid pressure is also controlled to keep the separating force within a selected margin of the force exerted on the bearing, to control wear of the bearing. Control of the separating force is achieved by selectively pressurizing individual hydrostatic pads, thereby effectively varying the active hydrostatic area of the bearing.

Abstract: The invention relates to a method for optimizing a grooved bearing pattern on a bearing surface of a fluid dynamic bearing for the purpose of improving the bearing properties as well as an appropriately designed grooved bearing pattern, the grooved bearing pattern having a defined length, width and depth, and the bearing surface being moveable with respect to another associated bearing surface in at least one direction of movement, having the following steps: selection of a bearing property to be improved, optimization of the geometry of the grooved bearing pattern in respect of the bearing property to be improved by adjusting one or more of the following parameters of the grooved bearing pattern: depth, width, length, angle with respect to direction of movement of the bearing surface or its normal, contour, geometry of the transition to adjacent surfaces.

Abstract: Fluid dynamic bearing systems produced by specified methods are provided. In one example, a method for designing a fluid dynamic bearing system includes determining a first stability ratio for a first journal bearing configuration. The method further includes determining a second stability ratio for a second journal bearing configuration. In a further example system, the first configuration has two sub-journal bearings and the second configuration has three sub-journal bearings. The method may comprise comparing the two stability ratios to determine whether adding a sub-journal increases the stability ratio of the bearing system.

Abstract: A fluid dynamic bearing is provided having a first surface having at least a first groove pattern formed therein; and the second surface having at least a second groove pattern formed therein; wherein one of the surfaces is configured to be rotated relative to the other surface. The groove patterns may be conventional patterns or patterns described herein. Further, the patterns discussed herein may be disposed wholly on each surface or may be divided between the two surfaces. The groove design is intended to be useable in either a journal, thrust or other fluid bearing design.

Abstract: The cross sectional shape of an axial direction communicating path when viewed in the axial direction is flat in the circumferential direction, and the cross sectional area of the communicating path gradually decreases moving from the center of the cross section toward the both ends in the circumferential direction. When a sleeve and a cover member are bonded with an adhesive, the adhesive is actively made to flow into an adhesive inflow portion.

Abstract: A fluid bearing device capable of responding to miniaturization while preventing an operating fluid such as a lubricating oil from leaking out to the outside. The fluid bearing device includes a shaft and a sleeve arranged on an outer periphery with respect to the shaft with a microscopic gap in between, and has an operating fluid filled in between the shaft and the sleeve. The shaft is formed by a sintered body, a radial dynamic pressure generating groove is formed on an outer peripheral surface of the shaft, and the sleeve is formed by a material not allowing the operating fluid to pass through. The shaft is thus covered by the sleeve formed by a material that does not penetrate the operating fluid such as lubricating oil from the outer periphery side, so that the operating fluid does not leak out to the outside even when the shaft is a porous body made of a sintered body.

Abstract: Disclosed is a lubricant composition comprising a base oil which contains 50% by mass or more of at least one of an ?-olefin oligomer and a hydrogenated product of an ?-olefin oligomer and in which the kinematic viscosity and the flash point satisfy the following relational equation (I): Flash point (° C.)?49×ln ?+90??(I) [provided that ? is a kinematic viscosity at 40° C.]. The lubricant composition contains a base oil which has little effect on a resin or elastomer because it is a nonpolar compound, in addition to having an extremely small amount of evaporation and a high flash point despite a low viscosity, and is suitable for various applications, in particular, as bearing oils.

Abstract: A bearing unit and a rotating apparatus which prevent leakage of lubricating oil to the utmost and which are superior in reliability are disclosed. A radial bearing and a thrust bearing support a shaft for rotation, and a path forming member and a path forming member lid form a communicating path having a function of short-circuiting pressure generated when the shaft and the radial bearing rotate relative to each other. A housing has a function of covering and holding the members mentioned while the housing is open at one end of the shaft with a small void left therebetween. Lubricating oil is filled in the void. The path forming member and the path forming member lid fully cover the members mentioned, except a shaft opening side portion of the radial bearing. The housing is made of a molded resin material.

Abstract: A hydrodynamic bearing device is provided for a spindle motor used in a hard disk drive or the like with a good state of fastening and good fastening strength between a shaft and a fixed member. The hydrodynamic bearing device includes a shaft that has a cylindrical main shaft portion and a fixing portion provided at one end of the main shaft portion, a sleeve that has a bearing hole in which the main shaft portion is inserted in a rotatable state, and a fixed member that is fixed to the fixing portion of the shaft. A nitride layer is formed on the main shaft portion, and a nitride layer non-forming film is formed on the fixing portion.

Abstract: A pod propulsion system comprises a housing defining a fluid duct and an annular drum rotatably mounted to the housing within the fluid duct. The annular drum has a drum interior and a cylindrical outer surface. The system further comprises a rotor mounted to the drum for rotation therewith, the rotor and the drum having a common axis of rotation. A bearing assembly mounted to the housing comprises a first bearing comprising a first plurality of bearing pads disposed circumferentially around the drum. Each pad has a pad bearing surface adapted to contact a first drum portion in a predetermined manner and is pivotably mounted to the housing so as to maintain contact of the pad bearing surface with the first drum portion in the predetermined manner when an orientation of the drum portion relative to the housing changes.

Abstract: A different-diameter clearance of high accuracy is created at low cost, thereby improving the bearing performance and the sealing capability. An inner periphery 5a of a molded part 5 having a step from an inner periphery 4a of an electroformed part 4 is molded to a nonconductive coating 9 which covers the surface of a master 8. When the nonconductive coating 9 is removed, a radial clearance 7 having a diameter greater than that of a bearing clearance 6 is created between the inner periphery 5a of the molded part 5, which is exposed to the interior, and an outer periphery 2a of a shaft member 2.

Abstract: A hydrodynamic bearing device in a hydrodynamic bearing device in which a sleeve (2) is covered with a cover (5), which is capable of easily confirming that a working fluid is favorably filled between the cover and the sleeve, and easily confirming that an adhesive (21) which bonds the cover and the sleeve is favorably filled, and an inspection method of an amount of the working fluid are provided. By using the cover having translucency, the filled state of the working fluid is visually recognized through the cover, and is confirmed with an image recognition apparatus.

Abstract: A fluid dynamic bearing motor and method are described, wherein motor components, including complex shaped motor components, are molded of plastic. The molding ensures form control and dimensional control thereby accomplishing design requirements, and eliminating or reducing component costs and component machining. The mold can be shaped to form various motor geometries, thereby eliminating the need for multiple component assembly and related assembly costs. In an aspect, a plastic integral motor hub is formed by injection molding. Alternatively, a plastic motor hub is affixed to a metal sleeve. In another aspect, fluid containment structures are molded into the motor component, reducing the number of components as compared with machined metal components. In a further aspect, bearing structures such as grooves are molded into the motor component, thereby eliminating processes such as electrochemical machining. In yet a further aspect, a plastic hub faces a thrustplate, reducing expensive sleeve machining.

Abstract: The invention relates to an oil-leak proof bearing system, and the system includes a bearing, an oil-leak proof cover and a rotor shaft. The center portion of the oil-leak proof cover defines a through hole, and the inner wall defining the through hole is provided with at least one first guiding groove thereon extended obliquely downward from the upper edge of the inner side face to force oil dispersed by the rotor shaft to flow back into the bearing system. The bottom surface of the oil-leak proof cover, contacting the bearing, is provided with second guiding grooves extending radially approximately from the center thereof. The capillarity of the second guiding grooves guides the oil dispersed by the rotor shaft to flow radially. The design of the first and second guiding grooves prevents the bearing system from leakage of lubricating oil, and provides a closed oil loop for operation.

Abstract: Embodiments of the invention make high-speed rotation of a magnetic disk, suppression of an increase in electric power consumption, and suppression in shaft falling vibration compatible together in a magnetic disk device. In one embodiment, a magnetic disk device comprises a magnetic disk that records information, and a drive unit that rotates the magnetic disk about a shaft. The drive unit comprises a rotary section that holds the magnetic disk, and a stationary section that supports the rotary section through a fluid bearing. The fluid bearing comprises a radial fluid bearing that bears a load in a direction perpendicular to an axial direction, and a thrust fluid bearing that bears a load in the axial direction. The thrust fluid bearing comprises a first thrust fluid bearing having a small diameter and a shallow clearance, and a second thrust fluid bearing positioned outside an outer periphery of a shaft and being larger in diameter and deeper in clearance than the first thrust fluid bearing.

Abstract: A hydrodynamic bearing device in a hydrodynamic bearing device in which a sleeve (2) is covered with a cover (5), which is capable of easily confirming that a working fluid is favorably filled between the cover and the sleeve, and easily confirming that an adhesive (21) which bonds the cover and the sleeve is favorably filled, and an inspection method of an amount of the working fluid are provided. By using the cover having translucency, the filled state of the working fluid is visually recognized through the cover, and is confirmed with an image recognition apparatus.

Abstract: A hydrodynamic bearing device is provided for use with a spindle motor. The hydrodynamic bearing device has a sleeve made of a sintered metal that is obtained by sintering a sintering material that is iron, an iron alloy, copper, a copper alloy or a mixture thereof. This sintered metal has independent pores, which do not communicate with each other, by selecting conditions for forming a desired sintered body within a predetermined range. The conditions includes a grain size of powdered metal of a material for the sintered metal, a molding pressure when the molded body is formed, sintering temperature and sintering period in the sintering step.

Abstract: Upon operation, flywheel assemblies sand other such rotational mechanisms are released by mechanical backup bearings, which then normally remain disengaged until shutdown as the flywheel assembly is levitated by the axial magnetic field. However, either due to over heating of bearings, power failure or other stimuli, flywheels often suffer a phenomenon deemed as touchdown down from the levitation state. During this touchdown event, flywheels inherently lose rotational momentum, thus ceasing to generate and release power and often cause damage to components as well as casing. Enhancements developed herein, through the introduction of the instant secondary hybrid touchdown bearing system, allow flywheels and other such systems to retain rotational momentum and continue generation of energy. Further, the instant system negates damage to system components, as well as bearing wear.

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: Multi-recess hydrostatic journal bearings support a rotating shaft and have inclined surfaces, each inclined surface forming a variable radial gap with the surface of the shaft, the variable gaps converging in the direction of rotation of the shaft to increase hydrodynamic forces, reduce a turbulent component of shear friction, and improve the thermal stability of the journal bearing. The inclined surfaces can be formed in one or more of portions of recess bottoms in recesses, portions of gap lands surrounding recesses, and portions of an inner surface of a bushing.

Abstract: Materials with different thermal expansion coefficients are selected individually for a bearing guide and a slider that constitute a fluid bearing. The guide and the slider are combined in close contact with each other (i.e., with a zero bearing clearance between the two) in a temperature environment different from a temperature at which the fluid bearing is actually used. In consequence, the bearing clearance at the operating temperature can be adjusted based on a difference from the temperature for the fluid bearing assembly.

Abstract: A contoured region is disposed within a capillary buffer of a Fluid Dynamic Bearing. In one embodiment, the contoured region comprises at least one defined edge for arresting the displacement of a lubricant within the capillary buffer.