Abstract: A hydrodynamic bearing having a shaft, which is fixedly connected at one end to a rotating component, and a bearing sleeve, which encompasses the shaft at its other free end with a slight clearance. The sleeve and the shaft form a concentric bearing gap. The shaft and/or the bearing sleeve is provided with at least one groove pattern which forms at least one radial hydrodynamic bearing. A volume equalizing cavity and at least one connecting passage connecting the bearing gap with the volume equalizing cavity extend radially outwards at an angle to the bearing gap.

Abstract: A fluid bearing with an oil circulating hole therein has a bearing housing fixedly assembled to a stator base having a closed bottom surface; and upper and lower bearing portions; and a thrust receiving portion to rotatably support a rotating shaft. An opening oil reservoir is in the bearing housing and a lower oil reservoir is formed at the lower portion thereof. An intermediate oil reservoir is located between the upper and lower bearing portions. The oil circulating hole is formed in parallel with the rotating shaft in order to communicate with the opening oil reservoir, the intermediate oil reservoir and the lower oil reservoir. A space is defined at an opening portion which is covered with a cap in order to prevent oil from leaking.

Abstract: An electrolytic machining method for electrolytically machining a workpiece is provided. The method uses a masking member having through-hole patterns that correspond to the shapes of concave parts to be formed in the workpiece. The masking member is brought in contact with a machining surface of the workpiece. An electrolytic solution is supplied and allowed to flow in the gap between the masking member and an electrode tool. The electrolytic solution is allowed to enter into and flow within the through-hole patterns of the masking member in order to electrolytically machine surfaces of the workpiece only in the through-hole patterns.

Abstract: A hybrid type hydrodynamic and hydrostatic bearing and its manufacturing method are disclosed by the invention. By making use of a penetrated dynamic pressure generating groove carved on the surface of the bushing inside the housing, the processing efficiency of the tiny grooves can be substantially improved. Also, after combining the housing with the bushing, and utilizing porous material that is able to preserve a lubricant, the pressurization by gas can be added externally on the surface of the porous material. After being sealed, the gas prepress can force the lubricant to fill the interval between the bushing and shaft. The bearing can achieve the effect of lubricating and supporting the shaft.

Abstract: A hydrodynamic bearing device in which an incline between the center line of a shaft and the center line of a sleeve can be eliminated, rotational precision improved, and NRRO reduced, characterized in that different bearing lengths (L1 and L2) are selected for radial bearing portions and that at least any one parameter selected from among groove depths of pressure generating grooves, groove angles formed between the grooves and the radial direction of an shaft, and groove width ratios [a/(a+b)] of groove width (a) in relation to the sum (a+b) of the groove width (a) and ridge width (b) is caused to vary among the plurality of radial bearing portions.

Abstract: A bearing material includes: a backing metal made of stainless steel; and a porous sintered metal layer integrated with at least one surface of the backing metal by means of a bonding layer, particles of an inorganic substance being contained in a dispersed manner at grain boundaries of the porous sintered metal layer, wherein the porous sintered metal layer containing the particles of the inorganic substance are composed of 4 to 10% by weight of tin, 10 to 40% by weight of nickel, not less than 0.1 and less than 0.5% by weight of phosphorus, and the balance consisting of copper.

Abstract: A pumping system is provided that includes a pump assembly and a motor assembly. The motor assembly has a bearing collar and a bearing sleeve concentric to the bearing collar. Preferably, the bearing sleeve includes at least one propeller blade that is configured to assist the movement of lubricant through the motor assembly. In another preferred embodiment, the motor includes a lubricant channel housed within a centrally located shaft. Lubricant is moved out of the lubricant channel through a shaft port and a blade port disposed in the propeller blade.

Abstract: An oil-circulating structure for fan comprises an oily bearing with a central axis hole for pivoting a fan shaft. An inner oil-collecting recess trench is formed in the central axis hole of the oily bearing and has an inner thread shape oil-guiding trench set inside. Radial through holes penetrate from two ends of the inner thread shape oil-guiding trench to outside wall of the bearing. An outer oil-collecting recess trench is formed on the outside wall of the bearing and is connected with the inner thread shape oil-guiding trench by means of the radial through holes. When the fan rotates, a lubricant in the inner oil-collecting recess trench is pushed by the rotating fan shaft to flow in-and-out between the outer oil-collecting recess trench and the inner oil-collecting recess trench through the inner thread shape oil-guiding trench and the radial through holes so as to achieve oil-circulation of the oily bearing in which the lubricant won't overflow through the end surface of the oily bearing.

Abstract: A hydrodynamic bearing system for use in a spindle motor, especially for the actuation of hard disk drives, wherein the bearing arrangement features a shaft and a sleeve which, supported by a lubricant circulating between their bearing surfaces, are rotatable relative to one another. A reservoir for the lubricant is formed by a recess provided in the shaft and the inner surface of the sleeve. The reservoir is provided in the area of the face of at least one opening in the sleeve. To enable the fill level of the lubricant in the reservoir to be checked, the recess is provided with tapering transitional areas contours of which form an acute angle with the cutting plane of the shaft.

Abstract: A dynamic pressure bearing apparatus provides a configuration in which the label on which desired data is visibly printed is arranged in a manner that the label does not overlap with a cover plate at least in the area where the label faces the rotary shaft in the shaft direction where the cover plate covers the opening of the bearing sleeve. Deformation of the cover plate that may occur during attachment of the label onto the cover plate is thus prevented. The position of the cover plate is leveled with the position of the label, which makes height reduction of the bearing apparatus possible. Subsequently, even when a relatively thick label is attached onto the frame, the dynamic pressure bearing apparatus can still be made thinner without adversely affecting performance or life thereof.

Abstract: A bearing device (10) for a motor (12) includes a bearing set (20) and a shaft (14). The bearing set includes first and second bearings (21, 26), which are made of sintered metallic material and ceramic material respectively. An annular recess (24) is defined in one end of the first bearing. The second bearing is received in the recess. Each bearing defines a central hole (22, 27). The central holes have a same diameter. The motor includes a rotor (30), a stator (32), and a bearing sleeve (34). In assembly, one end of the shaft is fixed in a center of the rotor. The second bearing is inserted into the recess. The bearing set is fixed within the bearing sleeve. The stator is fixed around the bearing sleeve. The shaft is rotatably received in the central holes. During operation, the shaft rotates smoothly and stably in the bearing set.

Abstract: A dynamic pressure bearing device, comprising: a shaft member; a bearing member relatively rotatably supporting the shaft member; a plurality of dynamic pressure generation parts provided on a peripheral face either of the shaft member or the bearing member; and a perfect circle part formed at least on a shaft end side at a region which is axially adjacent to the dynamic pressure generation part on the peripheral face where a protruded part and a recessed part are formed, wherein the dynamic pressure generation parts are respectively formed in a circumferential direction at equal angular intervals and extended in an axial direction so as to form a protruded part which makes a dimension of a minute gap between the shaft member and the bearing member to be the smallest and a recessed part which makes the dimension of the minute gap the largest, and the dimension of the minute gap in the perfect circle part is set to be the same as that in the protruded part.

Abstract: In a dynamic pressure bearing, when a step portion (1a) is formed on the inner peripheral surface (1b) of a sleeve (1) and radial dynamic pressure grooves (3) are formed on the inner peripheral surface of the step portion, the width (L) in the axial direction of the dynamic pressure grooves is set to be slightly smaller than the width (D) in the axial direction of the step portion. The dynamic pressure grooves of the sleeve are formed by electrolytic etching.

Abstract: A composite fluid dynamic bearing and its manufacturing method is disclosed. By machining a plurality of bearings independently, the grooves of each bearing have uniform slopes. Then the method of the invention combines the bearings, which have different slope of the grooves, to form a bearing module having pressure-generating grooves. In this way the precision of the machining grooves of bearings can be improved.

Abstract: Spindle motor utilizing a dynamic-pressure bearing device having a full-fill structure and capable of discharging air bubbles from the lubricating oil after it is charged into the bearing device, as well as air bubbles appearing in the oil due to cavitation in handling. Thrust and radial bearing sections are configured within bearing clearances in between the rotor, the shaft, and a shaft-encompassing hollow bearing member. A communicating passage enabling the oil to redistribute itself within the bearing clearances is formed in the bearing member. At least one ray-like groove that reaches from the radially inward edge of dynamic-pressure-generating grooves in the thrust bearing section to the rim of the shaft-encompassing hollow is furnished in the bearing member. When the motor rotates the air bubbles are stirred and minced by the ray-like groove, and migrate toward release at the single oil-air interface.

Abstract: Disclosed herein is a kinetic pressure bearing motor, which is provided with an auxiliary dynamic pressure generating means, thus allowing a motor shaft to be stably rotated at a high speed, and considerably reducing vibration, therefore enhancing the performance of the motor. The kinetic pressure bearing motor includes a support unit which is provided at an outer surface of a motor shaft, and a shaft holder which is fitted over an upper portion of the motor shaft. Further, grooves for generating dynamic pressure are formed on an outer surface of the support unit. An extension is provided at the shaft holder to support the support unit in such a way as to be in contact with the outer surface of the support unit having the grooves.

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 pump apparatus of simple construction has a bearing structure for which a lubricant is unnecessary. A flow passage for a refrigerant (liquid ammonia) is formed in a housing to provide communication between a suction port and a discharge port, and slide bearing members formed of amorphous carbon are provided in the housing to be fitted into the flow passage to support a rotating shaft. A drive for rotating the rotating shaft is constituted by a rotor, which is fitted into the flow passage and provided with the rotating shaft, and a stator, which is provided outside the housing to surround the rotor, and a pump body is provided midway the flow passage and connected to the rotating shaft to pump a fluid.

Abstract: To provide a manufacturing method of a dynamic pressure bearing device and a dynamic pressure bearing device to inject a proper amount of lubricating oil to a bearing unit by using a simple process without leaving air bubbles in the bearing unit. The bearing unit is exposed in an atmosphere of reduced pressure such as in a vacuum chamber or the like to evacuate air in a gap between a shaft body and a bearing. The proper amount of lubricating oil is dropped to an open end of the gap of the bearing unit by using a dispenser. The bearing unit is released to an atmospheric air to fill the lubricating oil into a gap of the bearing unit.

Abstract: A composite fluid dynamic bearing and its manufacturing method is disclosed. By machining a plurality of bearings independently, the grooves of each bearing have uniform slopes. Then the method of the invention combines the bearings, which have different slope of the grooves, to form a bearing module having pressure-generating grooves. In this way the precision of the machining grooves of bearings can be improved.

Abstract: The fixed shaft type spindle motor of the invention has a fixed shaft vertically installed on a base and a rotor hub supported to freely rotate by the fixed shaft through a bearing. The bearing is composed of a compound ball bearing, and a larger diameter portion of a stepped top-form connection member having the larger diameter portion and a smaller diameter portion is fixedly engaged with the upper end of the outer ring of the compound ball bearing. And, the smaller diameter portion of the connection member is fastened to the rotor hub. The rotary shaft type spindle motor has a rotary shaft vertically installed on the rotor hub, in which the rotary shaft is supported to freely rotate on the base through the bearing. The bearing is composed of a compound ball bearing, and the larger diameter portion of the stepped top-form connection member having the larger diameter portion and the smaller diameter portion is fixedly engaged with the lower end of the outer ring of the compound ball bearing.

Abstract: A motor or bearing which incorporates the use of a capillary seal adjacent a bearing race between the shaft and surrounding hub or housing. The seal may take a plurality of forms, including a straight capillary seal; a seal formed between the housing and a seal ball having different radius of curvatures (preferably with the housing internal surface having a larger radius); or a centrifugal capillary seal comprising a male cone supported on a fixed or rotating shaft, and a female cone supported on a housing. The use of a capillary seal rather than ferrofluid seal should also provide a reduction in resistance across the seal gap compared to a ferrofluid seal.

Abstract: A ceramic dynamic pressure bearing, includes: a first member having an outer periphery formed with a gap forming surface causing a radial dynamic pressure, and a second member having an inner periphery defining a through hole formed with a gap forming surface causing the radial dynamic pressure. The first member is inserted into the through hole as to form a radial gap. The first member and the second member make rotation relative to each other to cause a fluid dynamic pressure at the radial gap. The first member and the second member are composed of an alumina ceramic including: an aluminum 90% to 99.5% by weight, and an oxide sintering assistant 0.5% to 10% by weight. The outer periphery has cylindricity not larger than 1.0 &mgr;m, and roundness not larger than 0.5 &mgr;m. The inner periphery has cylindricity not larger than 1.5 &mgr;m, and roundness not larger than 1.0 &mgr;m.

Abstract: The radially inner surface structure of the bearing in accordance with the present invention mainly comprises a pair of guiding groove sets and a plurality of convergent points thereof. The guiding groove sets are individually extended clockwise and counterclockwise from either end and terminating in a vicinity of a corresponding end to define a plurality of convergent points. The guiding groove sets are intersected in a predetermined angle and each guiding groove set is consisted of a plurality of guiding grooves arranged in parallel.

Abstract: A hydrodynamic bearing device in which an incline between the center line of a shaft and the center line of a sleeve can be eliminated, rotational precision improved, and NRRO reduced, characterized in that different bearing lengths (L1 and L2) are selected for radial bearing portions and that at least any one parameter selected from among groove depths of pressure generating grooves, groove angles formed between the grooves and the radial direction of an shaft, and groove width ratios [a/(a+b)] of groove width (a) in relation to the sum (a+b) of the groove width (a) and ridge width (b) is caused to vary among the plurality of radial bearing portions.

Abstract: A spindle motor for a hard disk drive having a stationary component with a first bearing surface, and a rotating component with a second bearing surface located in opposing relationship with the first bearing surface. The first and the second bearing surfaces form a hydrodynamic bearing. A bearing gap is formed between the first bearing surface and the second bearing surface, the bearing gap being filled with lubricating fluid. An oil-free recess is provided in the motor for placement of electromagnetic components of the motor. The stationary component is provided with a first set of seal surfaces, and the rotating component is provided with a second set of seal surfaces. The seal surfaces of the first set are located opposite the seal surfaces of the second set and form a labyrinth seal sealing the bearing gap from the oil-free motor recess.

Abstract: A hydrodynamic bearing system for use in a spindle motor, especially for the actuation of hard disk drives, wherein the bearing arrangement features a shaft and a sleeve which, supported by a lubricant circulating between their bearing surfaces, are rotatable relative to one another. A reservoir for the lubricant is formed by a recess provided in the shaft and the inner surface of the sleeve. The reservoir is provided in the area of the face of at least one opening in the sleeve. To enable the fill level of the lubricant in the reservoir to be checked, the recess is provided with tapering transitional areas contours of which form an acute angle with the cutting plane of the shaft.

Abstract: A bearing device includes an oil impregnated sintered bearing that rotatably holds a shaft fixed to a rotor, and a bearing boss to which inner wall the bearing is fixed. An end of the boss is sealed with a cap. Plural grooves are formed on the inner wall of the cap, so that lubricant leaked out from the bearing can be retained therein and restored to the bearing. This structure extends the service life of the bearing.

Abstract: A dynamic pressure bearing device includes a dynamic pressure bearing member that generates a dynamic pressured by pressurizing a lubrication fluid by a dynamic pressure generation device, and supports a rotary shaft by the dynamic pressure generated in the lubrication fluid, a thrust dynamic pressure bearing member formed by an end face in an axial direction of the dynamic pressure bearing member and an end face in an axial direction of a rotary member that rotates together with the rotary shaft, which are disposed opposite each other in the axial direction, and a fluid sealing section for preventing the lubrication fluid in the thrust dynamic pressure bearing member from leaking outside, provided adjacent to an outer side section in a radial direction of the thrust dynamic pressure bearing member and defined by an outer circumference wall surface of the dynamic pressure bearing member.

Abstract: A bearing device is provided with an oil storage space. The oil storage space is an oil storage space that is formed in the bearing device, so that the lubricating oil stored in the oil storage space may gradually leak outward through the capillary pores of the bearing device, thereby slowing down the release velocity of the lubricating oil, and thereby increasing the lifetime of the bearing device.

Abstract: The porous oil-impregnated bearing 1 comprises a bearing body 1a made of a porous material, and oil retained in the pores of the bearing body 1a by impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing body 1a is formed with a bearing surface 1b opposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surface 1b has a first region m1 in which a plurality of hydrodynamic pressure generating grooves 1c inclined in one direction with respect to the axial direction are circumferentially disposed, a second region m2 which is axially spaced from said first region m1 and in which a plurality of hydrodynamic pressure generating grooves 1c inclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions m1 and m2.

Abstract: The porous oil-impregnated bearing 1 comprises a bearing body 1a made of a porous material, and oil retained in the pores of the bearing body 1a by impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing body 1a is formed with a bearing surface 1b opposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surface 1b has a first region m1 in which a plurality of hydrodynamic pressure generating grooves 1c inclined in one direction with respect to the axial direction are circumferentially disposed, a second region m2 which is axially spaced from said first region m1 and in which a plurality of hydrodynamic pressure generating grooves 1c inclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions m1 and m2.

Abstract: An air spindle is provided which allows high-speed operation without reducing the bearing stiffness in the air spindle by reducing the heat generation at bearing portions. By increasing the number of nozzles for the radial bearing or increasing the axial distance between the nozzles, the ratio of the supply air flow rate Q to the bearing stiffness H is set at 2-10 to release heat generation at the bearing portions to outside by the gas.

Abstract: A bearing assembly having a shaft member having a bearing race and a piezoelectric member opposing the bearing race is situated so that when a voltage is applied to it, it expands against the bearing race so that a preload of the bearing is varied. The assembly includes a rotor having two outer bearing races opposing the shaft's inner bearing races. The contact angle for the upper bearing races is different than for the lower bearing races. In one embodiment of the present system, the piezoelectric member is disposed between the shaft member and the bearing race for varying the radial position of the bearing race. In another embodiment, the piezoelectric member is disposed for varying the axial position of the bearing race. In one embodiment, the system includes a hydrodynamic bearing assembly having a stator member having a hydrodynamic surface and a rotor member having a surface facing the stator member hydrodynamic surface.

Abstract: In the dynamic bearing device, a chamfer having a larger percentage of surface openings is continuous to the outer diameter side of a lower end surface of a bearing member, which constitutes a thrust bearing gap of a first thrust bearing part. A lubricating oil in pores of the bearing member is supplied to a gap portion through the surface openings of the chamfer, so that the gap portion can be kept at a positive pressure without becoming a negative pressure.

Abstract: A method and apparatus for replenishing oil in a fluid dynamic bearing using a sleeve groove. The replenishing groove is formed in the sleeve surrounding the shaft so that centrifugal force drives the oil to move toward the radial bearings.

Abstract: A fluid bearing includes a foil assembly that supports a journal inside a stationary retaining member includes a cylindrical top foil that is positioned radially inward, a cylindrical mid-foil that is positioned outside the top foil and corrugated bump foils positioned outside the mid-foil. In order to suppress a small amplitude vibration of the journal in the low rotational rate region, the bump foils, are separated into six in the circumferential direction. In order to suppress the synchronous vibration instability phenomenon, the top foil and the mid-foil are wound in opposite directions from each other. In order to suppress the whirl instability phenomenon, the sum of the frictional damping forces generated by the lower bump foils is set to be larger than the sum of the frictional damping forces generated by the upper bump foils.

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: The invention relates to an extra-roll slide bearing system (20) for a paper/board machine or a finishing machine, surrounding a shaft (2) in a roll (1). The bearing system comprises a body section (5), which is formed with a bearing housing (7) provided with hydrostatic bearing elements (3, 3A) disposed around the shaft (2). The bearing elements are fitted with slide elements (4, 4A), having a sliding surface (16) directed towards the shaft (2). Between the slide elements (4) and the shaft (2) is a bushing (6), which is mounted on the shaft (2) for rotation therewith, said slide elements (4, 4A) being adapted to position themselves around the bushing (6) with the sliding surfaces (16) against the external surface of the bushing directed away from the shaft for supporting said shaft (2), and hence the roll (1), rotatably relative to the body section (5). The bearing housing (7) has its axial ends provided with end caps (8, 9), along with packing elements (12, 14) therefor, for sealing the bearing housing.

Abstract: There is provided a sintered oil retaining bearing that secures the stability of an oil film and achieves high running accuracy through management to exclude a variation in the size of surface openings in the bearing surface, particularly the presence of large holes, while making use of such advantages as the mass productivity, low noise and low cost features of sintered oil retaining bearings.

Abstract: A dynamic pressure bearing apparatus comprises a rotary shaft, a sintered oil retaining bearing rotatably supporting the rotary shaft, the sintered oil retaining bearing having an interior surface defining an internal surface configuration for generating dynamic pressure to thereby form a dynamic pressure bearing between the rotary shaft and the sintered oil retaining bearing. The internal surface of the sintered oil retaining bearing comprises in a peripheral direction thereof, a minimum-gap section, a large-gap section and a separation groove section. The minimum-gap section has the minimum gap between the rotary shaft and the internal surface of the sintered oil retaining bearing.

Abstract: A very thin lubricating coating on one or both of the facing surfaces defining the gap of the hydrodynamic bearing. The lubricant film would need to be 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 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: 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: The porous oil-impregnated bearing 1 comprises a bearing body 1a made of a porous material, and oil retained in the pores of the bearing body 1a by impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing body 1a is formed with a bearing surface 1b opposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surface 1b has a first region m1 in which a plurality of hydrodynamic pressure generating grooves 1c inclined in one direction with respect to the axial direction are circumferentially disposed, a second region m2 which is axially spaced from said first region m1 and in which a plurality of hydrodynamic pressure generating grooves 1c inclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions m1 and m2.

Abstract: A bearing comprises a rotating shaft, a sleeve which surrounds the outer wall of the rotating shaft and supports the rotating shaft in such a manner that the rotating shaft is rotatable, and a thrust bearing plate which is fixed to the sleeve and supports one end of the rotating shaft. A first herringbone pattern and a second herringbone pattern are formed either on the rotating shaft or on the sleeve, wherein the first herringbone pattern is located at a first side and the second herringbone pattern is located at a second side, wherein the first side is the side where the thrust bearing plate is located, and the second side is the side opposite the first side. The relation between width-A and width-B in the first herringbone pattern is expressed by 0<(A−B)<0.

Abstract: To provide a dynamic pressure bearing apparatus having high performance and excellent stability without hindering operations of appliances due to a leaked oil, the dynamic pressure bearing apparatus of the present invention comprises; a rotating shaft inclined in a predetermined direction from a vertical direction; a sleeve rotatably supporting the rotating shaft; an operating fluid for generating a dynamic pressure, the operating fluid being filled in a gap formed between the sleeve and the rotating shaft; and capturing means for capturing the operating fluid leaked from the gap, the capturing means being disposed on an outside surface of the sleeve in the predetermined direction.

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: There is provided a sintered oil retaining bearing that secures the stability of an oil film and achieves high running accuracy through management to exclude a variation in the size of surface openings in the bearing surface, particularly the presence of large holes, while making use of such advantages as the mass productivity, low noise and low cost features of sintered oil retaining bearings. In a sintered oil retaining bearing 11 having a bearing body 19 that is composed of a porous body formed of a sintered metal, that is formed with a bearing surface 18 opposed to the outer peripheral surface of a rotary shaft 1 through a bearing clearance and that is impregnated with lubricating oil or lubricating grease, it is arranged that surface openings in said bearing surface 18 are substantially uniform in size and that when the area of a single such surface opening is converted into the area of a circle, the diameter of such circle does not exceed 0.05 mm.

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 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.