Abstract: An axial bearing for a turbocharger contains a through hole for a shaft and at least one at least partially or completely circulating segment section on a first and second side of the axial bearing. At least one bearing surface is disposed in the segment section. At least one oil pocket is on the first side of the axial bearing. The oil pocket is connected to at least one recess opening outwards, the recess being configured such that it connects the oil pocket for oil supply purposes to the respective segment section and the bearing surface(s) thereof on the first and second side of the axial bearing.

Abstract: The invention relates to a fluid dynamic bearing pattern that is disposed on at least one bearing surface of the two bearing parts of a fluid dynamic bearing that are moveable with respect to each other along a direction of movement. The bearing pattern comprises two related grooved sections, each section extending at an acute angle with respect to the direction of movement and exerting a defined pumping effect on the bearing fluid found in the bearing when the bearing parts move with respect to each other. According to the invention, the first section is disposed at an angle ? and the second section at an angle ? with respect to the direction of movement, the two angles varying in size.

Abstract: A fluid dynamic bearing device includes a bearing sleeve including a radial bearing surface, a shaft member to be inserted to an inner circumference of the bearing member, and a radial bearing part for non-contact supporting the shaft member in a radial direction by a dynamic pressure action of a fluid generated in a radial bearing gap between the radial bearing surface of the bearing member and an outer circumferential surface of the shaft member. Additionally, a plurality of bearing sleeves are axially arranged, and each bearing sleeve is formed having different axial length with respect to one another.

Abstract: A fluid dynamic bearing formed by a microelectromechanical systems (MEMS) wafer-level batch-fabrication process is provided. The process results in a high performance and high reliability fluid dynamic bearing having features including higher bearing lifetime at high RPM, improved bearing stiffness, durability and thrust/restoring forces capabilities. The present invention is especially useful with small form factor disc drive memory devices having constraints in motor height, such as a 2.5 inch disc drive, requiring high performance including high rotational speed and large areal density. A sacrificial layer is utilized in the process to simultaneously form symmetrical facing surfaces of relatively rotatable components. The facing surfaces define, therebetween, a desired feature, such as a journal bearing, a thrust bearing, a fluid channel, a fluid reservoir, a capillary seal, pressure generating grooves, and other profile geometries.

Abstract: Provided is a bearing capable of satisfying demands for cost reduction and further quietness, and stably maintaining high support accuracy. A sliding bearing (4) includes an inner member (5) having a mounting surface (9) with respect to a rotary shaft (2), and an outer member (6) being arranged on a radially outer side of the inner member (5). A radial bearing gap is formed between an outer peripheral surface (5a1) of the inner member (5) and an inner peripheral surface (7a1) of the outer member (6), and a lubricating oil is interposed in the radial bearing gap. Further, between the inner member (5) and the outer member (6), sealing gaps (S, S) for maintaining an oil level of the lubricating oil on both axial sides of the radial bearing gap are formed. At least a part of the mounting surface (9) of the inner member (5) is made of a metal.

Abstract: A first sleeve rotatably extends around a shaft. First and second flanges are fixed to the shaft. A second sleeve extending around the first sleeve is fixed thereto. A first annular member fixed to the second sleeve surrounds the first flange. A second annular member fixed to the second flange surrounds a portion of the second sleeve. A first capillary seal includes a clearance between the first flange and the first annular member. A second capillary seal includes a clearance between the second annular member and the second sleeve. Lubricant is provided in the clearances in the first and second capillary seals. The second annular member and the second sleeve are designed so that the lubricant in the clearance in the second capillary seal can be viewed from a point in a radial position which is outward of the second sleeve as seen in an axial direction.

Abstract: A fluid dynamic bearing mechanism includes a stationary bearing portion including a sleeve portion, and a rotating bearing portion including an outer rotating portion. A lubricating oil is arranged between the stationary and rotating bearing portions. A first dynamic pressure groove array is arranged in an upper surface of the sleeve portion or a lower surface of the outer rotating portion. A second dynamic pressure groove array is arranged in a surface of the outer rotating portion or a surface of the stationary bearing portion in a region between the first array and a liquid surface. An end of the second array closer to the liquid surface is arranged radially inward of an opposite end of the second array. An upper end opening of a communicating channel defined in the sleeve portion is arranged radially outward of a radially inner end of the first array.

Abstract: In this type of fluid dynamic bearing device, a dynamic pressure generating part having high molding accuracy is formed at low cost. A rotating member 2 includes a shaft part 9, and a holding member 10 as a thrust member provided in one end of the shaft part 9. In a partial annular region of a lower end surface 10a1 of a disk part 10a making up the holding member 10, a region where a plurality of dynamic pressure grooves 10a2 and a plurality of sectioning parts 10a3 formed between the plurality of dynamic pressure grooves 10a2 to section the respective dynamic pressure grooves 10a2 are arrayed spirally is formed. The above-described dynamic-pressure-groove 10a2 arrayed region is opposed to an upper end surface 8a of a housing part 8, and forms a thrust bearing clearance of a thrust bearing part T between the dynamic-pressure-groove 10a2 and the upper end surface 8a during the rotation of the shaft part 9.

Abstract: An apparatus for inhibiting oil leakage is disclosed by which the oil leakage can be effectively inhibited with a simple structure, where the apparatus is extensively formed along an outer periphery of a rotation shaft at a position higher than at least an upper end of a bearing and is formed with an oil barrier that restrains oil rise.

Abstract: Disclosed is a motor device. The motor device according to an exemplary embodiment of the present invention includes a sleeve having a shaft hole expanding downwardly in an axial direction; a shaft having a head part having exposed to a top portion of the sleeve and a body part having a shape corresponding to the shaft hole; a rotor case combined to the head part and rotating in connection with the shaft; an oil sealing part formed between the rotor case and the sleeve and an oil interface to seal oil provided to have a taper shape; and a thrust dynamic part formed on at least one of the rotor case and the sleeve and pumping the oil interface in an inner-diameter direction from the oil interface at the time of the rotation of the rotor case.

Abstract: A spindle motor can suppress the generation of noise during swinging and the extend service life, and also suppress the increase in current consumption. The outside diameter of a thrust hydrodynamic groove is at least 10% of the outside diameter of a disk-shaped medium, and the depth of the radial hydrodynamic groove is greater than the depth of the thrust hydrodynamic groove. By adjusting to specific numbers, the angular stiffness in the thrust bearing is raised, and even if a disturbance torque should be applied, wear or noise caused by metal contact inside the bearing can be suppressed.

Abstract: Disclosed herein is a spindle motor having a fluid dynamic bearing as an oil gap formed between a rotator and a stator, wherein the stator includes a sleeve having a protruding part extending in a circumferential direction formed on the upper part thereof, the rotator includes a hub including an oil interface forming member positioned under the protruding part of the sleeve and coupled to the lower end thereof, and an oil interface of the oil gap is formed between the upper part of the oil interface forming member and the lower part of the protruding part of the sleeve.

Abstract: An annular groove is provided to the rotary portion and/or the fixed portion in a bearing seal portion, and its cross section has a shape approximated by an arc. The annular groove is such that the relationship between the groove width W in a direction following the surface constituting a bearing seal portion and the groove depth Dg in a direction perpendicular to the surface constituting the bearing seal portion is Dg/W<0.4.

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: With a hydrodynamic bearing device 10, a first gap G1 is formed between a shaft 12 and a sleeve 11. A second gap G2 is formed between a sleeve cap 16 and the sleeve 11, and holds a lubricant 17. A thrust bearing member 21 is disposed near the inner peripheral surface of a center hole 16a of the sleeve cap 16. A third gap G3 is formed between the thrust bearing member 21 and the sleeve cap 16, and is open to the atmosphere. A fourth gap G4 is formed between the thrust bearing member 21 and the sleeve 11. The lubricant 17 circulates along a circulation passage that includes a communicating path 11b, the first gap G1 and the second gap G2.

Abstract: A magnetic fluid is held by a magnetic field in a stationary state and by a centrifugal force during rotation, leaking and splashing of the magnetic fluid caused by the instability of the pumping of a dynamic pressure bearing are prevented without using a magnetic fluid with a high saturation magnetization value, and the service life of the dynamic pressure bearing is extended. For this purpose, a sleeve 3 having a protruding tubular section is fitted and fixed to the outer periphery of the shaft 1 having a thrust plate 2 formed in an axial vicinity so as to be rotatable relatively to the shaft, an annular cover 4 is formed outwardly from the thrust plate 2 in an axial direction, the radially inward end of the annular cover 4 serves as an opening, at least two clearance sections serve as a reservoir 10 for reserving the magnetic fluid, and a magnetomotive force member 15 is provided for concentrating the magnetic flux lines on the radially outer side of the end portion 13 of the magnetic fluid 12.

Abstract: A hydrodynamic bearing device has favorable bearing performance and long endurance life. A thrust bearing part of the hydrodynamic bearing device has a second thrust surface. In the second thrust surface, a dynamic pressure generating groove area having a plurality of dynamic pressure generating grooves is formed in at least a part thereof in a radial direction. The action of dynamic pressure of lubricating oil increases the pressure in a thrust bearing clearance between an end of a flange part of an axial member and the second thrust surface, to support the axial member in an axial direction in a non-contact manner. The dynamic pressure generating groove area of the second thrust surface is formed by press working. The difference in height between the inner and outer peripheral edges of the surface of the dynamic pressure generating groove area regulated between or equal to 0 and 2 ?m.

Abstract: A method manufacturing of a fluid dynamic bearing includes: forming a substantially linear groove having a length corresponding to a circumferential direction width of the dynamic pressure groove formed on the inner circumferential surface of a shaft housing hole portion, along the circumferential direction of a surface orthogonal to a first processing direction along the central axis direction of a work, by a byte that performs a micro alternating drive in a second processing direction orthogonal to the first processing direction; and extending the dynamic pressure groove that extends in the first processing direction by continuously forming the substantially linear grooves in the first processing direction by displacing the relative positions of the work and the byte in the first processing direction.

Abstract: Proposed is a fluid dynamic bearing system having a bearing bush, a shaft rotatably supported in a bearing bore of the bearing bush and a hub connected to the shaft. A bearing gap filled with bearing fluid and having an axial section is defined between the shaft, the bearing bush and the hub. A first and a second fluid dynamic radial bearing are disposed along the axial section of the bearing gap, the radial bearings being marked by grooved bearing patterns on the associated bearing surfaces of the shaft and/or of the bearing bush. The two radial bearings have a mutual distance dL measured from an apex line of the first radial bearing to an apex line of the second radial bearing. A separator groove is disposed in the bearing bush or in the shaft in the axial section of the bearing gap between the two radial bearings and has an axial length lS. According to the invention, the ratio between the distance dL and the length lS is greater than 5 (five).

Abstract: A fluid dynamic bearing includes an auxiliary bearing portion, a first radial bearing portion and a second radial bearing portion arranged along an axial direction of the fluid dynamic bearing, wherein the auxiliary groove formed in the auxiliary bearing portion is shallower in depth than the radial dynamic pressure groove formed in the first radial bearing portion, and wherein a gap size in the auxiliary bearing portion is set to be equal to or larger than a gap size in the radial bearing portions.

Abstract: In a disk drive device according to an embodiment, radial dynamic pressure corresponding portions are structured such that the diameters thereof expand toward the axial outside of the sleeve, and that the shaft is in surface-contact with each of the radial dynamic pressure corresponding portions when the rotational drive of the disk drive device is stopped. Further, a herringborn-shaped radial dynamic pressure groove is formed in each of the radial dynamic pressure corresponding portions. The radial dynamic pressure groove in each radial dynamic pressure corresponding portion is formed such that the axial outside length from the turned-back portion of the herringborn-shape is longer than the axial inside length therefrom.

Abstract: A typical dynamic bearing design comprises a ring shaped or circular thrust plate mounted at or near the end of a shaft, the shaft defining together with a surrounding sleeve a journal bearing by providing grooves on only one of the two surfaces facing the gap between the shaft and sleeve. On the ring shaped thrust plate supported by the shaft, the traditional upward thrust bearing defined between the lower face of the thrust plate and the facing surface of the sleeve is maintained; but no grooves are on the surface of the thrust plate distant from the shaft and a facing counterplate surface. Further, the journal bearing is defined to have an asymmetry so that a bias force pressure along the surface of the shaft toward the thrust plate is established.

Abstract: A fluid dynamic bearing formed by a microelectromechanical systems (MEMS) wafer-level batch-fabrication process is provided. The process results in a high performance and high reliability fluid dynamic bearing having features including higher bearing lifetime at high RPM, improved bearing stiffness, durability and thrust/restoring forces capabilities. The present invention is especially useful with small form factor disc drive memory devices having constraints in motor height, such as a 2.5 inch disc drive, requiring high performance including high rotational speed and large areal density. A sacrificial layer is utilized in the process to simultaneously form symmetrical facing surfaces of relatively rotatable components. The facing surfaces define, therebetween, a desired feature, such as a journal bearing, a thrust bearing, a fluid channel, a fluid reservoir, a capillary seal, pressure generating grooves, and other profile geometries.

Abstract: A fluid dynamic bearing apparatus includes a first minute gap, a second minute gap, a third minute gap, a fourth minute gap, and a fifth minute gap. A flow of a lubricating oil from the fifth minute gap to the fourth minute gap is caused by a plurality of dynamic pressure generating grooves arranged within the fluid dynamic bearing apparatus. This flow causes air bubbles mixed in the lubricating oil within the fifth minute gap to flow toward the third minute gap and be discharged to an outside through the third minute gap. In addition, a flow of the lubricating oil into the third minute gap caused by a centrifugal force accompanying rotation is inhibited.

Abstract: An apparatus and method for increasing the buffer volume in a fluid dynamic bearing is disclosed. One embodiment provides a thrust washer coupled with a shaft of a fluid dynamic bearing. In addition, at least one groove is provided on an outward facing side of the thrust washer. In so doing, the at least one groove increases a fluid capacity of the capillary buffer of the fluid dynamic bearing without requiring a change in the size or shape of a capillary buffer of the fluid dynamic bearing.

Abstract: Embodiments of the invention provide a magnetic disk drive having improved vibration characteristics and a reduced size. In one embodiment, a magnetic disk drive comprises: a motor shaft for rotating a magnetic disk; a sleeve for rotatably supporting the motor shaft; and a motor hub into which the motor shaft is press fit. The motor hub supports the magnetic disk and includes a projection portion having an inner surface and an outer surface. The inner surface is in contact with the press-fit motor shaft in directions perpendicular to the rotational axis of the motor shaft. The outer surface faces the sleeve.

Abstract: A fluid dynamic bearing includes a shaft to which a resin flange is fixed by insert molding. The process where the flange is fixed to the shaft by insert molding includes a flange forming process in which the flange, fixed to the shaft, is formed by injecting the resin into a filled portion in the lower mold through an upper mold, while cooling at least part of the shaft, arranged in a shaft arrangement portion in a lower mold, with cooling water circulating through a cooling pipe.

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

Abstract: A thinner fluid dynamic bearing capable of stable shaft rotation, a motor including the bearing, and a recording-medium driving apparatus including the bearing are provided. Pressure-generating grooves are provided in thrust surfaces of a thrust bearing portion 39 opposite a circular plate 35 and a stopper 33 to attract a working fluid from inner and outer edges of the thrust bearing portion 39 to a radially midway portion thereof as a shaft member 16 rotates relative to a support 22. One or more through-holes 48 are provided between inner edges of annular regions of the thrust surfaces in which the pressure-generating grooves are provided and the midway portion in the radial direction. The through-holes extend through the thrust bearing portion 39 in a central-axis direction of the shaft member.

Abstract: A fluid dynamic bearing having a shaft (12) and a bearing sleeve (11) rotatably supported relative to each other. At least one of the shaft and the bearing sleeve is made of steel or stainless steel made of by weight C: 0.6˜1.20%; Si: 1.0% or less; Mn: 1.0% or less; Cr: 10.5˜18.0%; Mo: 1.0% or less; S.: 0.03% or less; and Fe. The dynamic pressure bearing surface (20) is formed by ridges (22) remaining in between multiple dynamic pressure grooves (21) formed by electrochemical machining.

Abstract: Disclosed herein is a spindle motor which prevents a sleeve from being deformed because of residual stress during the welding of a stopper for preventing the removal of a rotating shaft to which a thrust plate is coupled. The spindle motor includes a rotating shaft having a thrust plate which is fitted over the upper portion of the rotating shaft to be perpendicular to the rotating shaft. A sleeve accommodates the rotating shaft to rotatably support the rotating shaft. A stopper is coupled to the sleeve to support the upper surface of the thrust plate, thus preventing the removal of the rotating shaft. A stress-blocking groove is formed in the sleeve in such a way as to be adjacent to the stopper, and prevents the sleeve from being deformed by residual stress generated when the stopper is coupled to the sleeve.

Abstract: The present invention provides a spindle motor which has superior operating characteristics. The spindle motor includes a stationary support shaft which is fastened to a base plate, a thrust plate which is fitted over the stationary support shaft, a sleeve which is rotatably provided around the stationary support shaft and is coupled to a rotor casing, and an annular stopper which is fastened to the sleeve or the rotor casing to support the lower surface of the thrust plate and prevent the sleeve from being removed. A first fluid sealing part is formed between the stopper and the thrust plate. The spindle motor further includes an annular sealing cap which is coupled to the sleeve or the rotor casing to store fluid between the sealing cap and an upper surface of the sleeve. A second fluid sealing part is formed between the sealing cap and the stationary support shaft.

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

Abstract: [Object] To manufacture at lower cost a shaft member for a fluid dynamic bearing device, which is excellent in accuracy of bearing surfaces and shape accuracy between the bearing surfaces, and which has high fixation strength between a shaft portion and a flange portion. [Solving Means] A shaft portion (21) is press-fitted to a flange portion (22), and a plastic working portion (31c) of a first jig (31) is pressed against an upper end surface (22a) of the flange portion (22), whereby the flange portion (22) is partially subjected to plastic deformation toward an inner peripheral side. With this, a caulked portion (23) is formed between the flange portion (22) and the shaft portion (21). Further, press-fitting and caulking are performed in a state in which both end surfaces (22a and 22b) of the flange portion (22) are bound by a second jig (32) and a third jig (33).

Abstract: In a hydrodynamic bearing device in which a radial bearing face having a dynamic pressure generating groove on a shaft or an inner periphery of a sleeve is provided and a clearance between the shaft and the sleeve is filled with lubricant, an annular depression is provided on one end face of the sleeve adjacent to a rotor hub and a cover plate for covering the depression is attached to the sleeve so as to define a reservoir for the lubricant or air for the purpose of preventing such a risk that absence of an oil film occurs in clearances of a bearing of the hydrodynamic bearing device due to outflow of oil upon forcing of the oil by air received into the bearing. A step portion is provided on the other end face of the sleeve such that the step portion and the reservoir are communicated with each other by a communication hole. During operation of the hydrodynamic bearing device, air in the hydrodynamic bearing device reaches the reservoir via the communication hole so as to be discharged from the reservoir.

Abstract: With a hydrodynamic bearing device 10, a first gap G1 is formed between a shaft 12 and a sleeve 11. A second gap G2 is formed between a sleeve cap 16 and the sleeve 11, and holds a lubricant 17. A thrust bearing member 21 is disposed near the inner peripheral surface of a center hole 16a of the sleeve cap 16. A third gap G3 is formed between the thrust bearing member 21 and the sleeve cap 16, and is open to the atmosphere. A fourth gap G4 is formed between the thrust bearing member 21 and the sleeve 11. The lubricant 17 circulates along a circulation passage that includes a communicating path 11b, the first gap G1 and the second gap G2.

Abstract: A fluid dynamic bearing is constructed to support stably a rotating body to which a non-uniform force is applied, and a hard disk drive (HDD) employing the fluid dynamic bearing is provided. The fluid dynamic bearing includes a journal bearing part supporting a rotary shaft in a radial direction of the rotary shaft, a thrust part formed at one end of the rotary shaft, a thrust bearing part facing the thrust part and supporting the rotary shaft in a longitudinal direction of the rotary shaft, and a plurality of grooves formed on a surface of the thrust bearing part and/or the thrust part. The plurality of grooves include a first groove group including a plurality of grooves having the same shape and arrangement, and a second groove group adjacent to the first groove group and including at least one groove asymmetric with respect to the grooves of the first groove group.

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

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

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

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

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

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

Abstract: A system and method are provided for sealing a fluid dynamic bearing motor. A first and a second folded fluid channel are shaped for maximizing bearing axial span and establishing angular stiffness, to resist gyroscopic rocking of the facing bearing surfaces. The first folded fluid channel is limited to occupying at least a portion of the same axial space as the bearing. A first and a second fluid sealing system are connected to opposite axial ends of the bearing. The first fluid sealing system forms an active pumping seal to pump fluid during motor rotation. In an aspect, a top cover attached shaft, and a single thrust surface are employed, allowing for a rigid motor structure and power reduction in applications including high rotational speed disc drives. Also, by employing a rigid shaft design, significantly lower amplitude radial vibration responses are exhibited at higher frequencies than prior art motor designs.

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

Abstract: A fluid dynamic-pressure bearing includes a rotatable shaft, a hub, a fixed portion, and a lubricating liquid. The hub includes a hub thrust bearing surface extending from the shaft outwardly in a radial direction and an annular surface. The fixed portion includes a fixed-portion upper thrust bearing surface facing the hub thrust surface and a flange surface facing the annular surface. The hub thrust bearing surface, the fixed-portion upper thrust bearing surface, and the lubricating liquid arranged therebetween form together an upper thrust dynamic-pressure bearing. The annular surface and the flange surface define an annular gap therebetween. An axial dimension of the annular gap is larger than a total of an axial dimension of an upper thrust gap between the hub thrust bearing surface and the fixed-portion upper thrust bearing surface and an average depth of upper thrust dynamic-pressure generating grooves of the upper thrust dynamic-pressure bearing.

Abstract: A fluid dynamic pressure bearing has an annular dynamic pressure generating face having a dynamic pressure generating groove, which draws a working fluid toward a midway position in the radial direction from the inside and outside of a thrust bearing plate in the radial direction when a shaft and a housing are rotated relative to each other. The dynamic pressure generating groove is provided on thickness direction end faces of the thrust bearing plate or on an inner surface of the housing, and an inner groove section is located on an inner peripheral side of the dynamic pressure generating face on the end faces and is recessed more than the dynamic pressure generating face in the thickness direction. A through-hole extends through the thrust bearing plate in the thickness direction so as to open to the dynamic pressure generating face, and a communicating cavity connects the opening portion of the through-hole and the inner groove section.

Abstract: A fluid dynamic pressure effect can be sufficient without receiving a large effect of viscous friction of lubricating oil with changes in the environmental temperature in which it is used, and smooth starting of the rotating shaft can be ensured by regulating the gap between the rotating shaft and bearing within a suitable range. An outer diameter of the bearing, D, a length in an axial direction of the bearing, L, a gap at a radial side which is between the rotating shaft and the bearing, C, and an inclining height of the bearing end surface to which the flange is faced, ?, satisfy the expression L/D<C/?. It is preferable that the inclining height, ?, be 2 to 6 ?m, the inner diameter of the bearing be 1 to 3 ?m, and the gap at a radial side, C, be 1 to 4 ?m.

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

Abstract: An annular groove is provided to the rotary portion and/or the fixed portion in a bearing seal portion, and its cross section has a shape approximated by an arc. The annular groove is such that the relationship between the groove width W in a direction following the surface constituting a bearing seal portion and the groove depth Dg in a direction perpendicular to the surface constituting the bearing seal portion is Dg/W<0.4.