Abstract: The invention relates to a fluid dynamic bearing having at least one first bearing part as well as a second bearing part that are rotatably supported with respect to one another about a rotational axis and separated from one another by a bearing gap filled with bearing fluid. Associated bearing surfaces of the bearing parts form a first and a second radial bearing that are marked by grooved bearing patterns disposed on at least one bearing surface. Between the radial bearings, there is a separator gap having an enlarged gap distance compared to the bearing gap. According to the invention, the ends of the grooved bearing patterns of the radial bearings adjoining the separator gap penetrate into the separator gap. This measure goes to prevent the creation of negative pressure at the ends of the grooved bearing patterns, as a result of which the formation of air bubbles is also reduced.

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: A dynamic pressure bearing manufacturing method, comprising the steps of forming a herringbone groove pattern on the outer peripheral surface of a cylindrical mask and a spiral groove pattern on the lower surface of the flange part thereof, inserting the mask in a dynamic pressure bearing and optical fibers into the mask, radiating light from an external light source to the mask through optical fibers to transfer the herringbone groove pattern onto the inner peripheral surface of the dynamic pressure bearing and, at the same time, radiating the light from the upper side of the flange part to transfer the spiral groove pattern onto the upper surface of the dynamic pressure bearing performing development, and forming a herringbone groove on the inner peripheral surface of the bearing by etching and a spiral groove on the upper surface thereof.

Abstract: A hydrodynamic bearing assembly (10) includes a bearing sleeve (11) defining a receiving chamber (113) therein, a bearing (12) received in the receiving chamber of the bearing sleeve, a sealing cover (15) mounted to an open end (112) of the bearing sleeve and including an enlarged section (153) adjacent to the bearing, a shaft (13) extending through the sealing cover and rotatably disposed in the bearing, on which a plurality lubricant pressure generating grooves are defined, and a lubricant retaining space (117) defined by the enlarged section of the sealing cover, an end of the bearing and the shaft for receiving lubricant therein. One of the sealing cover and the shaft defines a groove (134) therein, while the other one of the sealing cover and the shaft extends a flange (156) into the groove.

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: It is an object of the present invention to provide a bearing member having a highly accurate dynamic pressure generating portion stably at low cost. Dynamic pressure grooves (8a1) and (8a2) are formed as the dynamic pressure generating portions on an inner circumferential surface of the electroforming portion (10) by an electroforming process, and injection molding is performed by using a resin while inserting the electroforming portion (10), thereby forming a bearing member (8). A shaft member (2) is inserted into an inner circumference of the bearing member.

Abstract: In a fluid dynamic pressure bearing, upper herringbone grooves and lower herringbone grooves continuous with the upper herringbone grooves are formed on the inner peripheral surface of a sleeve by plastic deformation. In addition, an annular groove recessed radially inward is formed on the outer peripheral surface of the shaft in a location opposing the region where the upper herringbone grooves and the lower herringbone grooves adjoin.

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: An oil lift pocket for a bearing surface having a plurality of channels in communication with a supply port. The plurality of channels may be formed in a substantially bow shaped configuration. Each channel may extend from a supply port and terminate at an end and away from the supply port. The oil lift pocket greatly reduces friction in slow turning operations and reduces babbitt delamination, dead zones, and nonuniform support and lift as well.

Abstract: A hydrodynamic bearing assembly comprises a bearing (10) defining a bearing hole (12) therein, a shaft (20) rotatably received in the bearing hole with a bearing clearance formed between a bearing surface of the bearing and an outer surface of the shaft, and a cover (40) attached to a top end of the bearing. The bearing clearance is filled with lubricant. A locking groove (22) is formed in an outer periphery of the shaft. The cover defines a through hole (42) receiving the shaft at the locking groove. Interlocking devices are formed on the cover and the bearing to join the cover and the bearing.

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 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 method and apparatus is provided for allowing a molecularly thin film to be established on a surface of the gas fluid dynamic bearing. The film can be controllably replenished so that the problem of liquid lubricant starvation is overcome. A suitable non-sludging lubricant of low surface tension is held in a porous reservoir within the stationary portion of the bearing. This fluid migrates out of the reservoir to coat the contiguous bearing surfaces. Alternatively, the lubricant may be held in a porous reservoir within the rotating portion of the bearing; due to centrifugal force, as the rotating portion spins, the fluid is spun out and coats the opposite non-rotating surface. The reservoir may be replaced by a singular reservoir such as a simple hole, depression, cavity or groove filled with lubricant.

Abstract: A lubricant retention design for a fluid dynamic bearing design in a spindle motor utilizes a labyrinth gap that is formed between the sleeve and the shaft of the bearing. The gap is used in conjunction with a barrier film to impede the flow of lubricant into the lateral and axial vent holes during non-operational vibration, such as shipping and handling of the end product. In another version, a plug is located in the lateral vent hole. The plug has a very small passage that permits air to pass therethrough for atmospheric pressure equalization, but prevents the escape of lubricant into the vent holes. Alternatively, the plug may be formed from a non-wettable material such as porous foam or sintered material and provided with a larger opening. Yet another solution utilizes a combination of both the labyrinth and plug designs.

Abstract: A very thin lubricant coating is applied to one or both of the facing surfaces defining the gap of a hydrodynamic bearing to prevent wear of these surfaces. The lubricant film is necessarily very thin, in the range of about 10 Å to 1000 Å, so that the film is thin enough that it does not materially affect the performance of the hydrodynamic bearing gap which is about typically 1-10 &mgr;m. The thin lubricant film could be a perfluoropolyether (PFPE) or a mixture of PFPE or a phosphazine derivative. To improve the adhesion and lubricating performance, functional PFPE can be used. For pure metallic surface like steel, phosphate esters can also be used because of its affinity with the metallic surface, e.g., ferrous. For example, the film could be PFPE, or a mixture of PFPE and a phosphazine derivative. The lubricant should be chosen to be thermally stable, and non-reactive with the typical ambient environment.

Abstract: A motor and a cooling device include (a) a frame with an opening, (b) a frame-housing provided on the frame and having one open side, (c) a stator mounted on an outer wall of the frame-housing, (d) a sleeve fit into the frame-housing, (e) a thrust supporter formed unitarily with a bottom face of the frame-housing, (f) a shaft having an end supported by the thrust supporter, inserted into the sleeve and rotatably supported, (g) a rotor to which the shaft is mounted, (h) a magnet mounted on the rotor and being opposite to the stator, and (i) oil provided in a space between the shaft and the sleeve. This construction saves a fitted section of the frame and the thrust supporter, and improves the flatness of the bottom face of frame. As a result, oil-spill due to temperature change cycles can be avoided, and adherence between a heating element and the cooling device is improved, so that heat conductivity and cooling efficiency are increased.

Abstract: A hydrodynamic bearing assembly with improved activation features is provided. The opposing surfaces in the radial and thrust bearings have grooves 2 and 5 with depths shallower gradually towards the downstream flow of the fluid passing therethrough, for generating the uniform dynamic pressure distribution. This allows the dynamic pressure distribution to be leveled so as to increase the bearing supporting force and prevent the dew grom being generated. Any one or both of the opposing surfaces in the thrust bearing has the inclined surface from the inner portion towards the outer portion so that the gap between the opposing surfaces is extended to about 2 microns. This causes the contacting points thereof when halted to be closer to the axis so that the friction can be reduced and the driving torque can be reduced when restating the bearing assembly. This also prevent the contact in the thrust bearing due to the external oscillating motion.

Abstract: A hydrodynamic gas bearing structure includes a columnar shaft body (1) and a hollow cylindrical bearing body (2) arranged opposing the shaft body (1) with a space (3) maintained in the radial direction therebetween. In a cross section perpendicular to the central axis of the shaft body (1) and the bearing body (2), either the shaft body (1) or the bearing body (2) has a convex polygonal shape with at least ten vertexes. Accordingly, a hydrodynamic gas bearing structure can be obtained in which ½ whirl can be suppressed even at a high speed rotation of 20,000 rpm or higher and run out associated with the rotation can be suppressed.

Abstract: A motor has a support member, a bearing member mounted in a hollow space of the support member for undergoing rotation, a rotor member having a shaft portion disposed in a hollow space of the bearing member for rotation therewith, at least one magnet connected to one of the support member and the rotor member, and electromagnets connected to the other of the support member and the rotor member and in confronting relation to the magnet for generating a rotational magnetic field that coacts with the magnet to rotate the rotor member. At least one of an inner peripheral surface of the bearing member and an outer peripheral surface of the shaft portion of the rotor member has contact portions disposed in contact with the other of the inner peripheral surface and the outer peripheral surface to form lubricating gaps each disposed between an adjacent pair of contact portions and between the inner and outer peripheral surfaces.

Abstract: In a dynamic pressure bearing device which has a shaft (3), a bearing (10) rotatable relative to the shaft (3), and capillary seal portions (13, 14) for holding a lubricating fluid (15) in a bearing clearance and in which the shaft (3) and the bearing (10) are relatively rotatably supported by dynamic pressure of the lubricating fluid (15) in the bearing clearance is scattered by centrifugal force so that the lubricating fluid (15) is kept in a constant quantity by the capillary seal portions (13, 14).

Abstract: A double sleeve type dynamic bearing comprises a fixed shaft having at least one end fixedly mountable to an apparatus in which the bearing is utilized, a rotary sleeve arranged coaxially with the fixed shaft so that a first fine gap is formed therebetween, a fixed sleeve arranged coaxially with the rotary sleeve so that a second fine gap is formed therebetween, and a lubrication oil filled in the fine gaps. The first fine gap and the second fine gap each have an open end exposed to air outside the bearing and an opposite end that is not exposed to the air, the opposite ends being in communication with each other. A holding member holds the fixed shaft and the fixed sleeve and is disposed adjacent to a lower end surface of the rotary sleeve to form a third fine gap between the holding member and the lower end surface of the rotary sleeve. The third fine gap is formed with a thrust dynamic pressure producing groove, and opposite ends of the first and second fine gaps meet each other through the third fine gap.

Abstract: In turbocharger, particularly an exhaust gas turbocharger for an internal combustion engine with a turbine wheel and an impeller disposed on a common shaft which is rotatably supported by friction bearings to which lubricating oil is supplied by an oil supply, a turbine speed detection device is provided comprising a pressure modulating structure disposed on the shaft for modulating the oil pressure in the oil supply in accordance with the speed of the shaft and an oil pressure sensor is arranged in the oil supply for sensing the oil pressure modulations for determining the speed of the turbocharger

Abstract: Spindle motor hydrodynamic pressure bearing device having upper and lower radial bearing portions axially separated by an air space, established in the micro-gap between the outer circumferential surface of the motor shaft and the inner circumferential surface of the motor sleeve element, and upper and lower thrust bearing portions established on either side of a thrust plate flange at the lower end of the shaft. A micro-gap established between the thrust plate and an opposing base surface of a recess in the sleeve element accommodating the thrust plate is continuous with the lower radial bearing micro-gap. Lubricating oil in the micro-gaps is therein retained continuously between the lower radial bearing and the upper thrust bearing. The lower radial bearing generates hydrodynamic pressure acting axially outward (toward the upper thrust bearing), and the upper thrust bearing generates hydrodynamic pressure acting radially inward (toward the lower radial bearing).

Abstract: A shaft member 21 the flexible, austenitic stainless steel is cold worked, and in the cold working process, a cold working ratio is increased, whereby a surface of the shaft member 21 is hardened. Therefore, there is no need for a nitriding treatment for the surface hardening. The corrosion proof performance of the passive coating possessed by the stainless steel is kept as intact.

Abstract: A bearing mechanism eliminates the need for lubricating oil, is capable of generating enough radial dynamic pressure even in lower-speed regions, and yet can be easily surface-machined for the generation of radial dynamic pressure and manufactured with low cost. In at least either one of an outer circumferential surface 2a of a first member 2 or an inner circumferential surface 3a of a second member 3 (hereinafter, referred to as roughened surface), the two circumferential surfaces being opposed to each other with a bearing gap G therebetween, dot-like minute dips and bumps are formed dispersedly, by which the surface is roughened so that its center-line mean roughness is controlled within a range of 0.1 &mgr;m-1.0 &mgr;m.

Abstract: A shaft structure for rotational support by a non-ball type bearing includes a spherical rotation-supporting section and a non-spherical section. The spherical rotation-supporting section provides a support for the shaft when the shaft rotates in an axial hole of the non-ball type bearing, thereby reducing the frictional area between the shaft and the inner periphery of the axial hole of the non-ball type bearing.

Abstract: A rotary apparatus includes: a radial fixed member; a rotary unit rotatably supported on the radial fixed member; a radial dynamic pressure bearing portion at which the radial fixed member faces the rotary unit; and dynamic pressure generating grooves formed on the radial dynamic pressure bearing portion. The dynamic pressure generating grooves are asymmetrically formed with respect to a rotary axis of the rotary unit.

Abstract: A hydrodynamic gas bearing structure which can effectively prevent the half speed whirl phenomenon and prevent wear at the time of activation or stopping of rotation is implemented in a simple manner. The hydrodynamic gas bearing has a shaft body having an outer periphery, and a cylindrical bearing body opposing to the shaft body with a space maintained in the radial direction. The shaft body has a hollow portion extending in the axial direction. In a cross section vertical to the axial line of the shaft body, the hollow portion has a not-complete-round, symmetrical shape with respect to a line passing through the center of the cross section, for example, an approximately regular triangular shape.

Abstract: A hydrodynamic gas bearing structure which can effectively prevent the half speed whirl phenomenon and prevent wear at the time of activation or stopping of rotation is implemented in a simple manner. The hydrodynamic gas bearing includes a shaft body having an outer periphery, and a cylindrical bearing body arranged around the shaft body with a space maintained therebetween in the radial direction. The shaft body has a hollow portion extending in the axial direction. In a cross section perpendicular to the axial line of the shaft body, the hollow portion has a not-complete-round, symmetrical shape with respect to a line passing through the center of the cross section, for example, an approximately regular triangular shape.

Abstract: Electrostatographic printing apparatus with a recording member in the form of an endless belt (26), and an air bearing (50) for guiding such belt along an endless path, which air bearing includes two belt-supporting end sections (53, 54) with a certain circumferential size, arranged for producing supporting air cushions for supporting both marginal portions of the endless belt (26) while the belt (26) is angularly wrapped about the sections (53, 54), an intermediate section (59) located between such end sections (53, 54) for providing support for the belt (26) if a central portion thereof would tend to become displaced exaggeratedly inwardly of the bearing (50), and two air cushion relief sections (61, 62), each one located inwardly adjacent to a corresponding end section of the bearing (50), and having a circumferential size which is smaller than that of said end sections (53, 54).

Abstract: Provided is a hydrodynamic gas bearing structure which can prevent occurrence of whirl not only in high-speed rotation but also in low-speed rotation, reduces such frequency that a floating rotational frequency in starting or stoppage of rotation increases, and is capable of shifting the floating rotational frequency to a low rotational frequency side. The hydrodynamic gas bearing structure comprises a shaft body (1) and a bearing body (2). A groove (11) is formed on the outer peripheral surface of the shaft body (1). The groove (11) consists of at least two concave parts, whose depths substantially differ from each other, which are formed serially in the circumferential direction, and has a circumferentially asymmetrical shape in a cross section perpendicular to the axis.

Abstract: A flywheel quill with thrust plate and axial rotor guiding. Bronze thrust plates are attached to the hub of a flywheel and hydrostatic pads secured to the frame of a press are adjoining the bronze thrust plates, such that axial motion of the flywheel with attached thrust plates is limited and reduced.

Abstract: A motor having a shaft body, a generally disk-like thrust plate extending outwardly in a radial direction from an outer periphery surface of the shaft body, a cylindrical sleeve structure which forms a fine clearance between itself on one hand and the shaft body and the thrust plate on the other, with an amount of lubricant fluid maintained in at least a part of the fine clearance.

Abstract: A novel hydro-dynamic fluid bearing device is herein disclosed which comprises a cylindrical shaft, a substantially cylindrical bearing member for axially supporting the shaft rotatably in a cylindrical hole having a bottom surface, a supporting member fixed on one side of the shaft and the bearing member, and a rotation member fixed on the other side of the shaft and the bearing member and rotatably supported on the supporting member, grooves for generating hydro-dynamic fluid being formed on at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical hole of the bearing member, wherein the bearing member is made of a resin material, and the outer peripheral surface of the substantially cylindrical portion is fixed to an annular reinforcing member having a higher rigidity than the bearing member.

Abstract: An air bearing comprising a static shaft having a circumferential surface in a form which when developed into a substantially flat plane takes the form of a series of shallow sinusoidal waves having at least three wave peaks, wherein one of the peaks carries a groove extending longitudinally parallel to the shaft axis and which bearing further comprises a hollow support member mounted for rotation around the static shaft.

Abstract: A hydrodynamic bearing apparatus comprises a shaft and a bearing having facing hydrodynamic surfaces therebetween. Hydrodynamic pressure generating grooves are disposed on at least one of the facing hydrodynamic surfaces of the shaft and bearing. The apparatus relatively rotatably supports the shaft and bearing by the hydrodynamic pressure from a lubricant fluid filled between the facing hydrodynamic surfaces. One of the shaft and bearing, on which the hydrodynamic pressure generating grooves are formed, are made of a metallic material whose thermal expansion coefficient is smaller than that of a copper containing material. A working layer made of the copper containing material is formed on the hydrodynamic surface side of the metallic material. The surface of the working layer functions as the hydrodynamic surface. The hydrodynamic pressure generating grooves are formed on the working layer.

Abstract: A circumferential flow type dynamic pressure bearing 1 is comprised of a shaft 2 having a multiple-arc-shaped pressure generating surface and a circular sleeve 3 fitted on the shaft 2. The shaft or the sleeve is formed with a plurality of proximity portions 4 each of which is close in distance to the surface opposed thereto whereby the support force of gas is generated. A plurality of grooves 5 formed at locations spaced from each other by an angle obtained by dividing the circumference by the number of proximity portions 4 or a divisor thereof. Use of such bearing ensures compatibility with high-humidity environmental conditions by provision of grooves, and at the same time it is capable of eliminating or reducing noise generated by vibration caused by radial deviations of the shaft due to provision of the grooves.

Abstract: A cross-sectional shape of a shaft body 1 perpendicular to its axis O has a shape defined by a closed curve having a plurality of maximal points M.sub.1, M.sub.2 and M.sub.3 whose distances from the axis are maximized about the axis O and a plurality of minimal points N.sub.1, N.sub.2 and N.sub.3 whose distances from the axis are minimized. This cross-sectional shape has a groove forming region provided with one groove 1b.sub.1 at least between the maximal points M.sub.1 and M.sub.2. When a bearing body 2 rotates on a CCW side with respect to the shaft body 1, the groove 1b.sub.1 is so arranged that an outer peripheral length a.sub.1 in the forward rotational direction exceeds an outer peripheral length b.sub.1 in the reverse rotational direction.

Abstract: A hydrodynamic bearing apparatus and a method for manufacturing a hydrodynamic bearing apparatus consists of providing a shaft and rotatably fitting the shaft to a bearing. Hydrodynamic pressure generating grooves are cut on the bearing surface of either the bearing or the shaft. The bearing surface that has the hydrodynamic pressure generating grooves thereon faces another bearing surface so that the bearing and shaft rotate with respect to one another, and the bearing or the shaft that has a bearing surface having the hydrodynamic pressure generating grooves is comprised of a thick main body member and a thin sleeve fitted to the main body member. The thin sleeve is thinner and made of a softer material than the main body member, the thin sleeve is evenly deformed, and the hydrodynamic pressure generating grooves are cut on a surface of the thin sleeve.

Abstract: A self-acting air bearing includes a housing, a shaft member supported in the housing, a cylindrical member which is installed around the shaft member coaxially and rotatably, and which rotates and generates a dynamic air pressure and thereby the cylindrical member is floatingly supported from the shaft member. In the bearing, concavities and convexes are formed at a same interval in a peripheral direction in either an outer peripheral surface of the shaft member or an inner peripheral surface of the cylindrical member, and a wave of one cycle between a beginning position of the concavity and an ending position of the convex is a harmonic wave. A bearing with high stability at high speed and high accuracy and which has high stability at high speed and low unbalance vibration can be achieved.

Abstract: The present invention relates to a method and apparatus for cleaning air in a hard disk drive by gathering the air in the upper and lower portion of the disk and discharging it outwardly through the air discharging position in order to maintain an optimum condition of the air space and reduce the error rate of the hard disk drive.

Abstract: A dynamic pressure type fluid bearing device includes a rotary shaft, a hollow sleeve in which the rotary shaft is rotatably mounted, and at least two sets of dynamic pressure generating grooves formed in either an outer surface of the rotary shaft or an inner surface of the sleeve. In this construction, a value obtained from k.times.sin .beta. is made equal to about 0.1 or ranges from 0.09 to 0.12, where k=d/e, d is a width of the dynamic pressure generating grooves, e is an interval between neighboring dynamic pressure generating grooves, and .beta. is an angle of the dynamic pressure generating grooves relative to a direction of rotation of the rotary shaft.

Abstract: In a spindle motor for a driving a memory disk, a is closed space formed by a sleeve metal, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Abstract: A dynamic pressure pneumatic bearing device has a groove for generating a dynamic pressure and formed on an inner circumferential face of a rotating shaft or an outer circumferential face of a fixed shaft; each of these shafts being formed by an aluminum alloy; and a wear resisting film formed on each of the inner circumferential face and the outer circumferential face. Another dynamic pressure pneumatic bearing device is constructed by a rotating shaft having a cylindrical hollow and a fixed shaft inserted into this hollow. The fixed shaft has a bearing face opposed to an inner circumferential face of the rotating shaft and separated from this inner circumferential face with a predetermined clearance. Herringbone grooves for generating a dynamic pressure and recessed portions having the same depth as the herringbone grooves are formed on the bearing face.

Abstract: A dynamic-pressure gas bearing wherein a rotational shaft is disposed to surround an outer circumference of a stationary shaft or to be surrounded by an inner circumference of a stationary shaft, and a dynamic pressure is generated between the stationary shaft and the rotational shaft through rotation of the rotational shaft, characterized in that a water relief portion is provided. In a dynamic-pressure gas-bearing having a water relief portion, even when the bearing is used in a high-humidity environment or even when water (water vapor) contained in a gas liquefies due to high pressure, a pressure change, or the like, the water relief portion prevents a water film from being formed to thereby prevent an increase in a shear force acting between the stationary shaft and the rotational shaft.

Abstract: A dynamic-pressure gas bearing structure includes a columnar shaft made of a silicon-nitride-based ceramic sintered body, a hollow cylindrical sleeve opposed to the shaft as keeping a clearance in a radial direction, the sleeve being made of a silicon-nitride-based ceramic sintered body, and at least three flat face portions located on a peripheral surface of the shaft and at equal intervals to the circumference along the peripheral surface. The flat face portion includes a plurality of unit planes continuously formed at predetermined angles to a direction of the circumference on the peripheral surface of the shaft. The unit planes are formed so as to extend substantially in parallel with an axial direction of the shaft.

Abstract: In a spindle motor for a driving a memory disk, a closed space is formed by a sleeve, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Abstract: A self pressurizing journal bearing assembly includes a tubular housing having a bore defining a plain cylindrical journal bearing, and a cylindrical rotary shaft disposed coaxially therein. The shaft includes a plain cylindrical journal spaced radially inwardly of the bearing to define a journal bearing gap. A screw pump is defined in part by a portion of the shaft, and is disposed inside the housing bore in flow communication with the journal bearing for continually circulating a lubricant thereto under pressure upon rotation of the shaft for accommodating lubricant end leakage from the journal bearing.

Abstract: An integrated spindle shaft and the like and self-compensating hydrostatic bearing assembly, obviating the need for external bearing sleeve constructions, in which a cylindrical bearing bore is so provided having circumferential grooves connected to pressure supply and drain systems, and in which collection space pressure supply and fluid drain grooves are provided that cooperate with circumferential collector grooves and pockets, such that when fluid flows axially from the pressure groove areas across the shaft into the collector grooves, in proportion to the radial clearance between the shaft surface and the bore, in conjunction to the pocket opposite to the collector groove, to provide a restoring force in proportion to the radial displacement of the shaft.

Abstract: A helically continuous projection 1a is formed around a sliding surface 1A of a sliding bearing 1 at a given pitch p. The surface roughness h of the sliding surface 1A, including the projection 1a, is chosen to be equal to or less than one-half the height H of the projection. This provides a sliding bearing 1 which exhibits an improved running-in performance.