Abstract: Provided is a fluid bearing device with a hub part having high molding precision and dimensional stability and capable of being produced at low cost. An annular gate (14) is formed at a portion of a cavity (15) corresponding to an outer peripheral edge portion of a lower end surface (10c1) of a flange part (10c), and a molten resin (P) is filled into the cavity (15) through the annular gate (14) to form a hub part (10) made of resin. The hub part (10) molded by the injection molding exhibits a radial resin orientation through an entire periphery thereof. Further, an annular gate trace (16) is formed at the outer peripheral edge portion of the lower end surface (10c1) of the flange part (10c) of the hub part (10).

Abstract: The present invention pertains to a fluid dynamic bearing assembly for directing bubbles. The assembly includes a stator with a stator bearing surface. A rotor with a rotor bearing surface rotates with respect to the stator such that the rotor bearing surface opposes the stator bearing surface. Lubricating fluid is disposed between the stator bearing surface and the rotor bearing surface. Features disposed on either the stator bearing surface or the rotor bearing surface direct the bubbles such that the fluid dynamic bearing assembly does not require a recirculation channel.

Abstract: A fluid dynamic pressure bearing device includes a shaft, an annular member, and a rotating member. The annular member is fixed to or seamlessly defined with the shaft and is radially opposed to the rotating member. The annular member and the rotating member are covered with a seal member. A first gap is defined between the seal member and the annular member. A second gap is defined between the rotating member and the seal member. A third gap is defined between the annular member and the rotating member. The first gap preferably has a width smaller than that of the second gap but greater than that of the third gap.

Abstract: In this type of fluid dynamic bearing device, there is formed a resin member capable of suppressing the intrusion of a lubricating oil as much as possible even when carbon fibers are compounded. A housing part 7 as the resin member can be obtained by injection-molding a resin composition in which PPS is a base resin, and carbon fibers are compounded. The housing part 7 is in contact with an ester-based lubricating oil filled in the inside of the bearing. In this case, the plurality of carbon fibers bound with a binder material not containing an urethane resin are cut and the carbon fibers minced by cutting are compounded into PPS to thereby obtain the above-described resin composition.

Abstract: A fluid dynamic bearing apparatus with an increased adhesive strength between a component having an adhesion fixing face and a bracket is provided by appropriately controlling the adhesion gap. Materials for a bracket 6 and a housing 7 are selected so that the value obtained by dividing the linear expansion coefficient of the housing 7 fixed to the inner periphery of the bracket 6 by the linear expansion coefficient of the bracket 6 having a portion 6b for mounting a stator coil 4 of a motor is not lower than 0.5 but not higher than 2.0. An adhesion fixing face 7e formed on the outer periphery of the housing 7 is adhesively fixed to the inner circumferential surface 6a of the bracket 6 with an anaerobic adhesive or an epoxy-based adhesive.

Abstract: A flow bearing includes a first tubular body and a second tubular body. The first tubular body has a first outer surface and a first inner surface defining a first bore. A first bearing surface is positioned on the first inner surface. The second tubular body has a second outer surface and a second inner surface defining a second bore. A second bearing surface is positioned on the second inner surface. The second tubular body is concentrically disposed within the first bore of the first tubular body, with the first inner surface facing the second outer surface. The first bearing surface and the second bearing surface are engaged in close fitting relation and define a mud lubricated flow gap. A metering valve is positioned one of upstream or downstream of the flow gap to meter flow through the flow gap.

Abstract: The fluid dynamic bearing device includes a housing, two bearing sleeves fixed to the housing at positions axially spaced apart from each other, and a shaft member inserted along inner peripheries of the bearing sleeves. The housing includes a spacer portion protruding further radially inwardly than inner peripheral surfaces to which the bearing sleeves are fixed. An axial fluid path is formed in the spacer portion, and the axial fluid path communicates to flow paths formed by axial grooves of the bearing sleeves.

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: 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: One preferred embodiment of the present invention provides a dynamic pressure bearing formed of a porous material into a shape of a cylindrical sleeve, for rotatably supporting a shaft inserted thereinto, including a first groove portion being formed circumferentially in a part of the inner circumferential surface of the dynamic pressure bearing; a second groove portion being formed circumferentially in the inner circumferential surface of the dynamic pressure bearing so as to have an intervening portion of the inner circumferential surface of the dynamic pressure bearing interposed between the first groove portion and the second groove portion; and a connection groove formed in the intervening portion so as to link the first groove portion and the second groove portion, the connection groove having at a bottom surface thereof a porous open ratio lower than a porous open ratio at any portion except for the bottom surface in the intervening portion.

Abstract: Vane pump (10) mechanical losses are reduced by removing vane friction losses and replacing them with lower magnitude journal bearing fluid film viscous drag losses. A freely rotating cam ring (70) is supported by a journal bearing (80). A relatively low sliding velocity is imposed between the cam ring and the vanes (26). This permits the use of less expensive and less brittle materials in the pump by allowing the pump to operate at much higher speeds without concern for exceeding vane tip velocity limits.

Abstract: A fan with an anti-leakage device for an oily bearing includes a base, an axial barrel, a fan wheel and a bearing. The axial barrel extends from the base and provides a first end, a second end, a first oil storage groove at the second end. The fan wheel extends a spindle from the inner side thereof and provides a joining part surrounding an end of the spindle and being adjacent to the inner side of the first end. The bearing is received in the axial barrel and further includes an axial through bore, which provides two inverted cone shaped ends, and at least a second oil storage groove, which is provided at a wall surface of the axial through bore for being adjacent to the spindle closely. Thus, a closed circuit is formed for the lubrication oil flowing back to the bearing without leakage.

Abstract: A fan with an anti-leakage device for an oily bearing includes a base, an axial barrel, a fan wheel and a bearing. The axial barrel extends from the base and provides a first end, a second end, a first oil storage groove at the second end. The fan wheel extends a spindle from the inner side thereof and provides a joining part surrounding an end of the spindle to be adjacent to the inner side of the first end. The bearing is received in the axial barrel and further includes an axial bore, which provides two cone shaped ends, and at least a second oil storage groove, which is provided at a wall surface thereof for being adjacent to the spindle closely; and a reduced-curve end, which is opposite to the joining part. Thus, a closed circuit is formed for the lubrication oil flowing back to the bearing without leakage.

Abstract: A fluid dynamic bearing device having high bearing performance at low cost is provided. A bearing member 6 includes an inner diameter part 8 having a radial bearing surface and an outer diameter part 7 having a mounting surface for a bracket 5. Both the inner diameter part 8 and the outer diameter part 7 are made of a resin. The inner diameter part 8 is preferably formed of an oil-impregnated resin, and more preferably a porous resin, and the outer diameter part 7 is formed of a nonporous resin.

Abstract: According to the present invention, when processing shafts in a centerless grinding machine, engagement between the shafts is prevented without rearranging the shafts, and thus outer circumferential faces of the shafts can be precisely processed. A shaft 12 is used in a hydrodynamic bearing device, and includes a cylindrical column formed with an outer circumferential face 12a forms a hydrodynamic radial bearing portion, a tapped hole 12j that is formed at a first end of the cylindrical column, and a first projecting portion 12b formed at a second end of the cylindrical column. When the first end and the second end of the shafts 12 are arranged side by side in an axis direction, the first projecting portion 12b of the shaft 12 can not interfere with the tapped hole 12j of the other shaft 12.

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 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: The invention relates to a fluid dynamic bearing system that has a first bearing part and a second bearing part that is rotatable with respect to the first bearing part, both of which form a bearing gap filled with a bearing fluid between opposing bearing surfaces. The bearing gap has two open ends that are each sealed against the environment by means of sealing zones. Bearing patterns used to generate hydrodynamic pressure within the bearing gap are provided on at least two spatially separated bearing surfaces. According to the invention, the bearing system is designed as a segment step bearing suited for changed directions of rotation, the ends of the sealing zones open to the environment being disposed on a smaller radial diameter than the bearing gap. The bearing fluid is thus kept in the bearing gap by means of a centrifugal force since on rotation of the bearing, the bearing fluid is pressed towards the outside and not towards the openings in the bearing gap or the sealing zones respectively.

Abstract: A motor includes a support member (40) having a bearing housing (20) defining a bearing hole (21) therein, a stator assembly (50) mounted to an outer periphery of the support member, and a rotor assembly (60) having a rotary shaft (68) extending into the bearing hole and a permanent magnet (66) confronting the stator assembly. A bearing pattern (100) is formed on either of the bearing housing and the rotary shaft. The bearing pattern includes a number of first and second grooves (13, 16) arranged circumferentially in an alternate fashion. Each of the first grooves is in communication with one adjacent second groove at an edge of the bearing pattern. Lubricating oil filled in the bearing pattern to establish dynamic pressure to separate the shaft and the bearing sleeve in radial direction when the shaft rotates.

Abstract: A hydrostatic air bearing in which a journal rotates within a cavity formed within a bearing race, and a sleeve that rotates with the journal within the cavity of the bearing race, where the sleeve is formed of a porous metallic material that allows for a bearing fluid such as air to flow from a high pressure side of the journal to a low pressure side of the journal through the porous sleeve that acts to dampen the bearing fluid flow, and therefore dampen the bearing. Another embodiment is for a hydrodynamic air bearing with an annular sleeve arranged between the rotating journal and the bearing race, where the annular sleeve is formed of a porous metallic material to dampen air flow across the journal.

Abstract: A fluid dynamic bearing motor including a stationary sleeve, a rotating shaft axially disposed through the sleeve, a journal gap between the shaft and the sleeve, the gap defined by first and second interfacial surfaces of the shaft and sleeve, at least one set of fluid dynamic grooves formed on the first interfacial surface of the journal gap, and at least one step defined on the second interfacial surface of the journal gap.

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 system, method and means is provided for withstanding mechanical shock for use with fluid dynamic bearings. A sealing system is provided that withstands 1000 G shock events. In an aspect, a grooved pumping seal employed between a thrust plate and a shield, a thrust plate having spiral grooves, a fluid recirculation passageway, and a reservoir creates an asymmetric pressure gradient. In an aspect, fluid is retained and air is purged utilizing an enlarged fluid reservoir, axial channels and an angled fill hole. In an aspect, a shaft is attached to a top cover supplying radial stiffness, and an enlarged single-sided thrust plate improves dynamic parallelism.

Abstract: A spindle motor which allows appropriate formation of communicating hole for compensating a pressure difference due to an error in working of dynamic pressure generating grooves and other components, easy formation of dynamic pressure generating grooves and readily prevention of leakage of a lubrication fluid is provided. An outer cylindrical member is attached to a shaft, a radial hydrodynamic bearing and a thrust hydrodynamic bearing are provided between the outer cylindrical member and the sleeve, and communicating holes are formed between the shaft and the outer cylindrical member, and between the hub and the outer cylindrical member. Since the collared outer cylindrical member is attached to the shaft, the communicating holes can be readily formed. Also, since a thrust hydrodynamic bearing is formed between an opening of a communicating hole and a seal, a lubrication fluid is unlikely to leak from the seal portion.

Abstract: An electric machine having a hybrid bearing for the purpose of supporting a rotor with respect to a stator, the hybrid bearing consisting of a radial bearing, taking the form of a fluid dynamic bearing, and an axial bearing that is made up of magnetic elements, wherein the magnetic elements comprise at least one permanent magnet and one flux guide element that are disposed so as to be located opposite each other in a radial direction.

Abstract: In a radial minute gap between a substantially columnar shaft and an inner peripheral face of a substantially cylindrical sleeve, oil is retained and a radial dynamic pressure bearing is formed. A plurality of recessed portions are arranged in a circumferential direction on at least one of an outer peripheral face of the shaft and the inner peripheral face of the sleeve and a first hill portion is provided to an axial end portion of each the recessed portion. Thus, it is possible to achieve a dynamic pressure bearing with which sufficient radial shaft support can be obtained in spite of a short axial length.

Abstract: A lubricating system for a fan (10) includes a lubricant storage space (17) formed at an end portion of the fan for receiving lubricant therein. A lubricant temporary retaining space (145) is defined at the other end portion of the fan for temporarily retaining the lubricant therein. A lubricant returning space (125) communicates the lubricant storage space with the lubricant temporary retaining space for enabling the lubricant to flow from the retaining space to the storage space. The returning space is defined in a tube (12) made of plastic, wherein a bearing (13) is mounted in the tube and a stator (15) is mounted around the tube.

Abstract: This invention provides a hydrodynamic bearing assembly which realizes a high rotation rate in a stable manner with robust rigidity. The hydrodynamic bearing assembly has a total radial gap of 3 microns or less for preventing contact with the thrust bearing. The thrust bearing is a pump-out type, and the radial bearing has offset grooves on the surface thereof to supply fluid flow to the thrust bearing. A depth ratio of the grooves relative to the diameter of the shaft is preferably 0.005 or less to avoid reduced translational rigidity.

Abstract: An image forming apparatus includes a chassis, a motor, a drive transmission gear that receives rotational force from the motor, a feed roller rotatably supported by the chassis, an intermediate gear that has a circular bearing, receives rotational force from the drive transmission gear, and transmits rotational force to the feed roller gear, and a gear support axle that is inserted through the bearing of the intermediate gear for rotatably supporting the intermediate gear. The gear support axle is provided with a bearing engagement part. The bearing engagement part has at least one flat section, at least one circular section, and at least two support portions formed between the flat section and the circular section, such that the gear support axle is supported by the bearing at at least one of the two support portions.

Abstract: This invention relates to an oil retaining structure of a spindle, wherein the outer peripheral surface of the spindle is provided with a first oil groove extending spirally along a clockwise direction and a second oil groove extending spirally along a counterclockwise direction. The first oil groove and the second oil groove across each other so as to form a plurality of collecting points. In operation, the oil film formed on the outer peripheral surface of the spindle will collect in the two oil grooves slowly, and the lubricating oil in the two oil grooves will bump into each other at the collecting points and then diffuse. As a result, an interior cycle is formed, which not only prevents the leaking of the lubricating oil but also makes the lubricating oil distribute evenly on the surface of the spindle.

Abstract: A fluid dynamic bearing unit includes a bearing housing (20) axially defining therein a bearing hole (21), a rotary shaft rotatably received in the bearing hole with a radial space formed between the rotary shaft and the bearing housing, and lubricant filled in the radial space. A ventilating path (25) is formed in a wall of the bearing housing to communicate a bottom of the bearing hole with an exterior of the bearing housing.

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.

Abstract: The present invention provides sliding members respectively having sliding surfaces opposed to each other for creating dynamic pressure in a fluid, in which the sliding surfaces are formed of ceramics containing crystal grains of Al2O3, crystal grains of TiC contained in the crystal grains of Al2O3, and crystal grains of TiC existing independently of the crystal grains of Al2O3, and having a TiC content of 5 to 20 mass % in the total amount of Al2O3 and TiC, and the respective volume resistivity values R1 and R2 of the ceramics forming the sliding surfaces are within a range simultaneously satisfying equations (1) to (3) to prevent spark discharges from being induced between the sliding surfaces, and a fluid dynamic pressure bearing and a motor to which the configuration is applied: 106 ?·cm<R1?1012 ?·cm??(1) 106 ?·cm<R2?1012 ?·cm??(2) |R1?R2|?105 ?·cm??(3)

Abstract: A fan motor includes an integral bearing member (40?) defining therein an axial inner bearing hole (21?) and forming a ventilating path (25?) in a wall portion thereof to communicate a bottom of the bearing hole with an exterior of the bearing member, a stator assembly (50) mounted to an outer periphery of the bearing member, and a rotor assembly (60) comprising a rotary shaft (68) extending into the bearing hole and a permanent magnet (66) confronting the stator assembly. Lubricating oil is filled between the rotary shaft and bearing member to establish dynamic pressure to separate the rotary shaft and the bearing member in radial direction when the rotary shaft rotates.

Abstract: A hydrodynamic bearing device capable of inhibiting leakage of a working fluid to an outside of a bearing and preventing reduction in radial bearing rigidity, and capable of keeping a gap between a thrust bearing and a radial bearing favorable and rotating stably. The hydrodynamic bearing device includes a shaft relatively rotatably inserted into a bearing hole of a sleeve, a radial bearing surface having dynamic pressure generating grooves formed on at least one of an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve, and a gap filled with a working fluid between the shaft and the sleeve. The shaft is made of high manganese chrome steel or stainless steel, and the sleeve is entirely made of sintered metal of metal particles including at least 60% by weight of iron or copper. Resin, metal or water glass is impregnated in pores on a surface of the sintered metal and cured.

Abstract: An oil repelling agent to coat a dynamic pressure device, such as a fluid dynamic pressure bearing device, includes a UV coloring agent, a fluorine-based polymer and a solvent. In an exemplary embodiment of the invention, the concentration of the UV coloring agent component is about 100 PPM to about 400 PPM, and the concentration of the fluorine polymer is about 0.1% by weight to about 0.6% by weight.

Abstract: Provided is a fluid dynamic bearing motor in which a rotor is rotatably supported by forming an oil gap between the rotor and a stator to form a fluid dynamic pressure bearing and a plurality of oil grooves are formed in a surface of the rotor or stator forming the oil gap and facing each other. The oil grooves include a first oil groove inclined at a first angle with respect to a circumferential direction, and a second oil groove extending from an end portion of the first oil groove and inclined at a second angle with respect to the circumferential direction. The first angle is formed relatively greater than the second angle.

Abstract: A fluid dynamic bearing is provided having two surfaces rotatable with respect to each other, a lubricating medium located in a gap between the two surfaces during rotation of the bearing, and an interrupted and offset groove pattern formed on one of the two surfaces to distribute the lubricating medium over the surface of the bearing. The groove design is intended to be useable in either a journal, thrust or other fluid bearing design.

Abstract: A MEMS (micro-electromechanical system) device having a rotor 44, a stator 43 and a shaft 27 connected to the stator 43 and around which the rotor 44 rotates. Grooves 47 are formed in a portion of the rotor 44, such that when the rotor 44 rotates an air bearing is formed for supporting the rotor 44 and maintaining its distance from the shaft 27 and stator 43. The rotor 44 is formed from joining two substrates 13, 23. One of the substrates 13 includes a surface having openings 7 including frustoconical walls, and one of the substrates 23 includes a surface having openings 15 including walls perpendicular to the surface of the substrate. The openings in the two substrates are in register with each other so that pairs of the openings form chambers 24. Each chamber 24 is provided with a shaft 27, which is positioned with a wide section of the shaft trapped in the chamber 24. The wide section of the shaft has a frustoconical surface facing the frustoconical walls of the chamber 24.

Abstract: A lubricating oil guiding system for a motor includes an axial tube, a first bearing mounted in the axial tube, a second bearing mounted in the axial tube, at least one separating plate securely mounted to the inner periphery of the axial tube, and at least one auxiliary oil chamber defined between the first bearing, the separating plate, and the shaft for distributing lubricating oil to the first bearing and for storing, buffering, and guiding the lubricating oil. A shaft of a rotor extends through the first bearing, the second bearing, and the separating plate. The first bearing defines an oil circulating loop and the second bearing defines an oil circulating loop. The separating plate is located between the first bearing and the second bearing to avoid mutual interference between the oil circulating loop of the first bearing and the oil circulating loop of the second bearing.

Abstract: The invention relates to a hydrodynamic bearing having a shaft, a bearing sleeve that encloses the shaft with a short radial spacing forming a concentric bearing gap, and an equalizing volume that is disposed between an outer circumference of the bearing sleeve and a covering cap at least partly overlapping the bearing sleeve and firmly fixed with respect to the bearing sleeve and connected to the bearing gap via at least one connecting channel or gap, a bearing fluid filling the bearing gap and the connecting channel/gap fully and the equalizing volume at least partially and the bearing fluid forming a continuous fluid film between the bearing gap and the equalizing volume.

Abstract: An oil-retaining structure for fan comprises an oily bearing with a central axis hole for pivoting a fan shaft. An oil-collecting recess trench is formed on an inside wall of the central axis hole. There is an acute angle oil-guiding ring edge correspondingly formed at one side of the oil-collecting recess trench. When the fan rotates, lubricant inside the oily bearing is upwardly sucked and blocked by the acute angle oil-guiding ring edge, and returns to the oil-collecting recess trench so as to construct an internal-recycle oil-retaining system.

Abstract: This invention is to provide a hydrodynamic bearing assembly, which realizes the high rotation rate in a stable manner and the robust rigidity. The hydrodynamic bearing assembly has a total radial gap of 3 microns or less for preventing the contact in the thrust bearing. The thrust bearing is a pomp-out type one, and the radial bearing has offset grooves on the surface thereof to supply the fluid flow sufficiently to the thrust bearing. The grooves also eliminate a half-whirl. A depth ratio relative to the diameter of bearing is preferably 0.005 or less to avoid the reduced translation rigidity. The radial gap is smoothly enlarged from the center to both ends along the axis, and the shaft is biased to incline the shaft relative to the sleeve, so that the shaft can be rotated with the robust rigidity. Also, a pair of the thrust bearings is provided on both ends of the radial bearing so as to realize the robust rigidity.

Abstract: A brushless motor includes a highly reliable thrust-receiving member that simplifies the machining and assembling of parts and prevents deformation of the bearing and leakage of lubricating oil. A stator base has a cylindrical portion serving as a base portion of a bearing housing of the motor. The cylindrical portion is integral with the stator base. A sleeve bearing is pressed in and mounted in a fixed condition on the inner side of the cylindrical portion. A stator core consisting of a conductive wire is mounted in a fixed condition on the outer side of the cylindrical portion, thereby forming a stator. A thrust-receiving portion for the rotary shaft is molded integrally with the stator base at the opening of the cylindrical portion by outsert and resin integral molding, this thrust-receiving portion serving to receive the end of the rotary shaft opposite to the output end thereof.

Abstract: In the present invention, in order to provide a fluid dynamic bearing, having heat resistance, wherein the electrical charging on a rotation portion is prevented and the torque loss caused by a lubricant is made lower, an ionic liquid or the like is added to the lubricant filled in the clearance between the opposed faces of a shaft and a sleeve unit as an electrical conductivity imparting agent.

Abstract: The invention relates to a gas bearing of a rapidly rotating shaft, whose end supports a tool, in particular to a gas bearing of a rapidly rotating shaft, whose end supports a polygon mirror (27) for a spindle of an optical application. To provide radial support along the shaft (3), gas bearings are arranged in a housing (5), whereby a first gas bearing (9) and a third gas bearing (8) are positioned concentrically in relation to one another and a second gas bearing (2), which is located midway between the first gas bearing (9) and the third gas bearing (8), is mounted in an eccentrically offset manner to the first gas bearing (9) and the third gas bearing (8). The invention is also provided with an adjusting device (1) for increasing the eccentric offset of the second gas bearing (2) as the rotational speed of the shaft (3) increases.

Abstract: A motor (100) having a dynamic pressure fluid bearing is composed of a hub (2), a rotor (4) provided with a shaft (7) of which one end portion is securely fastened by the hub (2) and another end portion is formed with a flange (8), and a stator (3) composed of a sleeve section (9) for axially sustaining the shaft (7) so as to be rotatable freely and a thrust plate (10) secured on the sleeve section (9) so as to confront with the flange (8), wherein the dynamic pressure fluid bearing is composed of a thrust dynamic pressure fluid bearing constituted by the flange (8) and the thrust plate (10), and wherein the shaft (7) is provided with a through hole (17) bored through the shaft (7) from the one end surface to the other end surface, and wherein the through hole (17) is formed in a shape having an opening to the other end surface of the shaft (7) by way of a funnel shaped section (17c) of which diameter gradually increases toward the other end surface of the shaft (7).

Abstract: A dynamic pressure bearing is provided in which required performances such as corrosion resistance and wear resistance in the use of a hard disk drive or the like are realized without application of any coating such as Ni plating that easily causes a failure, thereby exhibiting stable performances for a long time with a high production yield. As solving means for the above, the material of a sleeve is set to a copper alloy which contains a brass composed essentially of copper (Cu) and zinc (Zn), and silicon (Si), and which does not contain a low-melting soft metal component. A hard phase consisting of a compound of brass and silicon, and a soft phase consisting of brass are mixedly present in a matrix form. According to the configuration, the free-cutting property, the wear resistance, and the corrosion resistance are improved, and a coating by hard Ni plating or the like is not required. Since a low-melting soft metal component is not contained, a working fluid is prevented from being deteriorated.

Abstract: A variable-gap fluid dynamic bearing motor assembly is described. In one embodiment, the assembly includes a hub configured to rotate about a rotational axis and to support at least one disc. The assembly also includes a first member attached to the hub and configured to rotate about the rotational axis and a second member. A first fluid dynamic journal bearing having a first bearing gap and a second fluid dynamic journal bearing having a second bearing gap are disposed between the first member and the second member. The bearing gaps are configured such that the second bearing gap is larger than the first bearing gap. Bearing fluid disposed within the first fluid dynamic journal bearing and the second fluid dynamic journal bearing to support the relative rotation of the first member and the second member.

Abstract: This invention generally relates to reduction drive assemblies and, more particularly, to belt and pulley reduction drive assemblies and related support structure for portable equipment to mix and aerate materials. The support structure is adapted to provide support to a jack shaft and any associated bearing assemblies and to facilitate adjustment and tightening of various components of the reduction assembly.