Abstract: A fan vibration absorbing structure includes a bearing cup and a vibration absorbing element. The bearing cup includes a first section, a second section and a bearing holding hole. The first and the second section are connected end-to-end to enclose a receiving space therein, which communicates with the bearing holding hole. The vibration absorbing element is fitted between the first and the second section. With the fan vibration absorbing structure included in a fan, it is able to largely reduce the vibration occurred during fan operation.

Abstract: An alignment stage including: a base plate; one or more X direction thrust generation guide mechanisms for generating thrust and performing guidance in the direction of a straight line X; a pair of lower plates disposed above the X direction thrust generation guide mechanisms; a pair of upper plates provided corresponding to the lower plates, respectively; a pair of rotatable bearings disposed between the lower plates and the upper plates; one or more Y direction thrust generation guide mechanisms for generating thrust and performing guidance in the direction of a straight line Y perpendicular to the straight line X; and a table plate disposed above the Y direction thrust generation guide mechanisms. With this configuration, it is possible for the alignment stage to be compact and easy to assemble.

Abstract: There is provided a fluid bearing including: a sleeve having a bearing hole; a shaft being inserted into the bearing hole to be rotatable with respect to the sleeve; a thrust portion that is fixed to the sleeve and covers one end portion of the bearing hole; and a liquid filled in a gap between the sleeve and the shaft. The bearing hole is configured to have a first portion having a first diameter; a second portion that is located at an end portion that is closer to the thrust portion than the first portion, the second portion having a second diameter that is substantially the dame with the first diameter; and a groove that is located at a position between the first portion and the second portion.

Abstract: A resolver can have a stator installed in a housing simply, without requiring a special jig. In the resolver including a housing and a stator core fixed in the housing, the stator core is fixed to the inside of the housing by rotating relative to the housing.

Abstract: An electric fluid pump includes: a case including a recess portion into which a fluid flows; a rotor arranged in the recess portion; an axial member supporting the rotor; and a flange member insert-molded with the case and the axial member, secured to an end portion of the axial member, and buried in a bottom wall portion of the recess portion, wherein the flange member includes: a first flange portion; a reduced portion closer to an inner surface of the bottom wall portion than the first flange portion, and smaller than the first flange portion in a radial direction; and a second flange portion closer to the inner surface than the reduced portion, larger than the first flange portion in the radial direction, and partially exposed from the inner surface, and the inner surface is flat.

Abstract: A fan structure includes an upper cover, a fan frame body, a bearing cup, a bearing, a stator assembly, a hub and a shaft rod. The upper cover is mated with the fan frame body to together define a receiving space in which the bearing cup is disposed. The bearing cup has an open end and a closed end. The bearing is disposed in the bearing cup. The stator assembly is fitted around the bearing cup. The hub has multiple outward extending blades spaced from the upper cover by a first distance. The shaft rod has a connection end connected with the hub and a protruding end passing through the shaft hole and protruding from the bearing to abut against the closed end of the bearing cup and define a second distance. The first distance is smaller than the second distance to avoid deflection of the shaft rod.

Abstract: A fluid bearing apparatus includes a stationary member and a rotating member. A bearing surface of the stationary member and a bearing surface of the rotating member are arranged opposite to each other with a minute gap intervening therebetween. A lubricating fluid is arranged in the minute gap. At least one of the bearing surfaces includes a dynamic pressure groove, and a plurality of striations defined in a bottom portion of the dynamic pressure groove. Each of the dynamic pressure groove and the striations is arranged to extend in a direction at an angle greater than 0° to a circumferential direction. An angle defined between each striation and the circumferential direction is equal to or smaller than an angle defined between the dynamic pressure groove and the circumferential direction. Thus, an improvement in a force of dynamic pressure at the dynamic pressure groove is achieved.

Abstract: Provided is an apparatus, including a stationary component; a rotatable component, wherein the stationary component and the rotatable component are positioned for relative rotation; a first sealing means positioned in a radial channel at a first axial end of the rotatable component; a second sealing means positioned in an axial channel at a second axial end of the rotatable component; and a fluid reservoir adjacent to the first sealing means and extending radially outward from the first sealing means, wherein the fluid reservoir is positioned radially outward from the pump seal, and wherein the fluid reservoir extends radially outward from the pump seal.

Abstract: Accurately formed critical tolerance fit components are provided for fluid dynamic bearing motors, including disc drive memory systems. In an aspect, critical tolerance fit components are molded to a metal insert and include a portion of a hub, a disc seating surface, and a disc locating surface. The insert includes another portion of a hub, a sleeve, or a disc clamp retainer for a novel disc clamp. In an aspect, the plastic component is situated to cause the thermal expansion of the plastic to be restricted by the thermal expansion of a metal insert. Expensive machining of a stamped metal hub is minimized or eliminated by using the molded component portions. Strict component tolerances are provided as needed for perpendicularity relative to motor rotation for seating a disc with accurate flatness, a circumferential surface for centering the disc, and tight parallelism between a disc mounting surface and a center shaft.

Abstract: This set of roller bearings, which is a grounding bearing for a rotary machine, comprises a first-angular contact rolling bearing having a first outer race, a first inner race and first rolling elements, a second angular-contact rolling bearing having a second outer race, a second inner race and second rolling elements, a mount in which the first angular-contact rolling bearing and the second angular-contact rolling bearing are mounted. The first outer race and the second outer race are arranged in the mount either directly one beside the other or via the interposition of an intermediate member, the axial stiffness of which is greater than that of the mount and than those of the first and second outer races. Application for example to asynchronous motors.

Abstract: An electric motor has a rotor that is rotatably arranged around a rotor shaft. The rotor is mounted by way of at least one outer bearing that is arranged at a radial distance from the rotor shaft. The rotor has an annular design and is connected to the rotor shaft by way of at least one flexible connecting element.

Abstract: Disclosed therein is a fan motor including: a lower bracket having a lower protrusion which is located at the central portion and has a lower bearing insertion portion therein and a space which is formed around the lower protrusion; an upper bracket having an upper protrusion which is located at the central portion and has an upper bearing insertion portion therein; a rotor located between the lower protrusion and the upper protrusion and rotating together with a shaft; and a stator core surrounded by a lower insulator which is located above the lower protrusion and an upper insulator which is located below the upper protrusion.

Abstract: A motor base includes a bottom plate and at least one vibration reduction unit. The bottom plate has opposite top and bottom surfaces. A shaft-coupling portion is arranged on the top surface. The at least one vibration reduction unit encloses the shaft-coupling portion. Each of the at least one vibration reduction unit includes at least one protrusion and at least one groove. The at least one protrusion is arranged on one of the top and bottom surfaces. The at least one groove is correspondingly arranged on the other one of the top and bottom surfaces.

Abstract: A motor includes a base, a stator, and a rotor. The base includes a shaft tube having an open end and receiving an inner assembly. The stator is mounted to an outer periphery of the shaft tube. The rotor is rotatably coupled to the inner assembly. The stator includes an insulating bobbin unit having an extension extending in a radial direction to the open end of the shaft tube. The extension includes an engagement hole. The shaft tube includes a positioning member having an engaging section engaged in the engagement hole. The insulating bobbin unit is fixed by an end of the engaging section. The engagement stability of the stator is enhanced by engagement of the positioning member of the base and the insulating bobbin unit.

Abstract: An aircraft power generating assembly having a mechanical gear transmission, and an electric machine integrated in the mechanical transmission; the electric machine having a stator connected directly to a fixed frame of the mechanical transmission, and a rotor surrounding and rotated by a rotary shaft of the mechanical transmission; and the opposite ends of the rotary shaft being connected to respective further rotary input/output shafts.

Abstract: A fluid dynamic bearing device (21) includes: a shaft member (22); a housing (29) as an outer member which is arranged on a radially outer side of the shaft member (22) and is opened at both ends; a radial bearing gap which is formed on a radially inner side of the housing (29) and faces an outer peripheral surface of the shaft member (22); and a lid member (30) closing an opening on one end side of the housing (29), wherein the lid member (30) is fitted to an outer peripheral surface of the housing (29) with a fastening allowance which does not affect accuracy of a surface defining an outer diameter dimension of the radial bearing gap so that the housing (29) and the lid member (30) are bonded and fixed to each other.

Abstract: A starter includes an output shaft which rotates by a rotary force applied from the motor unit, a housing in which an end of the output shaft is rotatably supported, and an electromagnetic device configured to apply/shut off current to the motor unit, and biases a suppressing force toward the ring gear to the pinion gear through a clutch mechanism, wherein a load receiving member which abuts one end of the output shaft to receive an axial load generated from the output shaft is installed in the housing.

Abstract: A spindle motor includes a base portion and a bearing mechanism. A fixing region, which includes a first region at which the base portion and the bearing mechanism are fixed to each other and a second region at which a seal gap is defined between the base portion and the bearing mechanism, is located between an inner circumferential portion of the base portion which defines a through hole and an outer circumferential portion of the bearing mechanism. The inner circumferential portion of the base portion has, at least in the second region, a degree of surface roughness greater than a degree of surface roughness of the outer circumferential portion of the bearing mechanism. The seal gap gradually decreases in radial width with increasing height, and includes an adhesive along an entire circumference of the seal gap.

Abstract: The invention relates to an electric machine, comprising a stator (2), a rotor (3), a split cage (4), which separates a wet region (5) from a dry region (6), control electronics (9) and an interconnection element (7, 8), which produces an electrical contact between the stator (2) and the control electronics (9), wherein the rotor (3) is arranged in the wet region (5), wherein the interconnection element (7, 8) is surrounded at least partially by an insulating element (10), and wherein the insulating element (10) divides the dry region (6) into a first subregion (60), in which the stator (2) is arranged, and a second subregion (61), in which the control electronics (9) are arranged.

Abstract: Radial magnetic bearings (125) of a centrifugal gas compressor (100) may lose power and fail to support the shaft (120) resulting in damage to the shaft (120). Auxiliary bearings (135) may be used to support the shaft (120) during such a failure. A landing guard (140) may be installed as a sacrificial piece between the shaft (120) and the auxiliary bearings (135). Landing guard (140) includes slots (144) that may be used with pins (121) in the shaft (120) to prevent an angular displacement between the landing guard (140) and the shaft (120).

Abstract: A housing assembly for an electric motor having a rotor shaft rotatable about an axis includes a housing cover and a housing case. The housing cover defines a first bearing seat for rotatably supporting a first portion of the rotor shaft. The housing case defines a second bearing seat for rotatably supporting a second portion of the rotor shaft. At least one of the housing cover and the housing case includes a plurality of mounting lugs substantially circumferentially evenly spaced about the shaft axis for mounting the electric motor to a surface.

Abstract: A plain bearing of a shaft, in particular of an electric-motor drive unit of a motor vehicle, contains a first plain bearing part that surrounds the shaft and a second plain bearing part connected axially to the first plain bearing part. The thermal expansion coefficient of the second plain bearing part is greater than the thermal expansion coefficient of the first plain bearing part.

Abstract: A bearing apparatus includes a bearing portion; a shaft; an upper thrust portion; a rotor cylindrical portion extending downward from an outer edge portion, and arranged radially outward of the bearing portion; and an annular seal cover fixed to an outer circumferential surface. A seal portion having a surface of lubricating oil defined therein is defined in a seal gap defined between an inner circumferential surface of the rotor cylindrical portion and an outer circumferential surface of the bearing portion. The seal cover includes a fixing portion fixed to the outer circumferential surface of the rotor cylindrical portion; and an inner flange portion extending radially inward from the fixing portion below a lower end portion of the rotor cylindrical portion, and having an inner circumferential portion arranged opposite to the outer circumferential surface of the bearing portion to define a vertical gap together with the outer circumferential surface.

Abstract: A measuring head for a coordinate measuring machine for determining spatial coordinates on a measurement object has a coupling part for detachably receiving a measurement tool. The coupling part has a number of first bearing elements, a magnet and a retaining pin. The measurement tool has a disk with a number of second bearing elements, an anchoring plate and at least one adjustable locking element. The magnet is configured to attract the anchoring plate so as to bring the first and second bearing elements into engagement with one another. The first and second bearing elements, in the engaged state, define a defined position of the measurement tool on the coupling part. The at least one locking element secures the measurement tool to the retaining pin. The anchoring plate is detachably secured to the disk and the at least one locking element retains the anchoring plate on the retaining pin.

Abstract: A power generating bearing assembly providing a bearing retained by a bearing housing. The bearing housing includes a bearing cooling passage system having at least one integrated liquid cooling passage integrated within the bearing housing. A turbine receiving bore is formed through the bearing housing, penetrating the integrated liquid cooling segment. A turbine assembly is inserted into the turbine receiving bore, positioning a turbine blade subassembly of the turbine assembly within the integrated liquid cooling passage, wherein fluid flowing within the integrated liquid cooling passage causes the blade subassembly to rotate. The rotation of the blade subassembly rotates an electric power generator to create electric power. The turbine assembly can include an electro-magnetic subassembly mounting plate, wherein the turbine subassembly is located on an interior surface of the mounting plate and at least a portion of the power generating portion located on an exterior portion of the mounting plate.

Abstract: A power generating bearing assembly (100) comprising a bearing (120) retained by a bearing housing (110). The bearing housing (110) includes a bearing cooling passage system comprising at least one integrated liquid cooling passage (130) is integrated within the bearing housing (110). A turbine receiving bore (160) is formed through the bearing housing (110), penetrating the integrated liquid cooling segment (130). A turbine assembly (200) is inserted into the turbine receiving bore (160), positioning a turbine blade subassembly (230) of the turbine assembly (200) within the integrated liquid cooling passage (130), wherein fluid flowing within the integrated liquid cooling passage (130) causes the blade subassembly (230) to rotate. The rotation of the blade subassembly (230) rotates an electric power generator (collectively 222, 224, 226, 240, 242, 244, 246) to create electric power.

Abstract: Provided herein, is an apparatus that includes a stationary component, a rotatable component, and an upper journal bearing and a lower journal bearing. The upper journal bearing and the lower journal bearing are defined in a gap between the stationary component and the rotatable component, and the stationary component and rotatable component are configured for relative rotation. A thrust bearing is disposed between the upper journal bearing and the lower journal bearing.

Abstract: A power generating bearing assembly comprising a bearing retained by a bearing housing is provided. The bearing housing includes a bearing cooling passage system comprising at least one integrated liquid cooling passage is integrated within the bearing housing. A turbine assembly is inserted within the integrated liquid cooling passage, wherein fluid flowing within the integrated liquid cooling passage causes a turbine blade subassembly within the turbine assembly to rotate. The rotation of the turbine blade subassembly rotates an electrical power generator to create electrical power. The turbine assembly can be integrated into any existing bearing assembly comprising a bearing cooling passage system. It is preferred to seat the turbine assembly within a cooling system port of the bearing cooling passage system.

Abstract: A fluid dynamic bearing motor is provided having relatively rotatable facing surfaces that are reliably lubricated. A radial gap is defined between the relatively rotatable facing surfaces, wherein a first axial end of a fluid dynamic bearing has a larger radial gap as compared to a central region of the fluid dynamic bearing. In an aspect, a fluid recirculation passageway is established between the first axial end and the central region of the fluid dynamic bearing. In an aspect, a fluid reservoir is formed axially above the first axial end of the fluid dynamic bearing. Robustness of the FDB motor is increased, and sensitivity to external loads or mechanical shock events is reduced. Dry surface-to-surface contact of bearing surfaces and reduced performance or failure of the motor or disc drive components is averted. The use of diamond-like coating on relatively rotatable fluid bearing surfaces may also be reduced or eliminated.

Abstract: A stator includes a stator core and a plurality of coils. The stator core includes a core-back, a plurality of teeth portions, and a plurality of lug portions. Each of the plurality of teeth portions includes a coil winding portion and a tip end portion. The core-back includes a slanted portion. An axial position of a magnetic center of the rotor magnet radially outward of the stator overlaps with an axially extending range of the tip end portion. A thickness of the slanted portion in a direction perpendicular or substantially perpendicular to an upper surface of the slanted portion is smaller than an axial thickness of the coil winding portion.

Abstract: A recirculation fan includes a casing, a covering member, and a fan assembly. The casing has a base. The covering member is coupled with the casing to define an accommodation space. The fan assembly is disposed within the accommodation space, and includes a first impeller, a second impeller, a motor, and a plurality of magnetic elements. The second impeller is located beside the first impeller. The motor is fixed on the base of the casing and connected with the first impeller for driving rotation of the first impeller. The magnetic elements are arranged between the first impeller and the second impeller. A wind force generated by the first impeller and a magnetic torque resulted from a magnetic vortex of the magnetic elements cause contactless rotation of the second impeller.

Abstract: An electric motor has a rotor that is rotatably arranged around a rotor shaft. The rotor is mounted by way of at least one outer bearing that is arranged at a radial distance from the rotor shaft. The rotor has an annular design and is connected to the rotor shaft by way of at least one flexible connecting element.

Abstract: An axial flux electrical machine including a housing, a stator located within the housing, a rotatable shaft carried by the housing by means of at least a main bearing, and a rotor fixed to the shaft within the housing. Magnetic attractive forces between the rotor and the stator produce an axial thrust on the main bearing and a biasing means (preferably in the form of a spring) is arranged to urge the shaft in a direction opposite to the axial thrust so as to reduce the net load on the main bearing. This reduction in net load on the main bearing increases bearing life and improves motor efficiency.

Abstract: A motor includes a stator, a rotor tube which is disposed inside the stator, a rotor core assembly which is coupled to an outer circumferential surface of the rotor tube, and a shaft which is coupled in the rotor tube. The rotor tube is divided into at least two stepped regions having different diameters. A multiple-row bearing has an inner wheel coupled to an outer circumferential surface of any one of the at least two stepped regions, and rotatably supports the rotor tube. Such a configuration ensures structural stability of the motor and minimizes a space occupied by a bearing.

Abstract: A bearing support plate for use in a generator has a radially enlarged flange with a first cylindrical portion extending from the flange in one direction which will provide a bearing support for an outer race of a ball bearing, and a radially inner cylindrical portion extending in an opposed direction that will be away from the ball bearing relative to the flange. The flange is generally cylindrical but has a truncated portion over a circumferential extent. The first cylindrical portion is formed with radially enlarged portions with intermediate radially thinner portions. The flange includes bolt holes circumferentially aligned with the radially thinner portions.

Abstract: A spindle motor includes a bearing assembly, a base plate, a stator, a rotation shaft, a rotor, an adhesive member arranged at a space formed by the bearing assembly and a burring unit and a strength reinforcement member including a body fixed to a bottom surface of the base plate.

Abstract: There are provided a hydrodynamic bearing assembly and a motor including the same. The hydrodynamic bearing assembly includes a sleeve rotatably supporting a shaft and including a first circulation hole formed therein, the first circulation hole penetrating between an inner peripheral surface thereof and an outer peripheral surface thereof; a sleeve housing into which the sleeve is inserted; and a second circulation hole formed between the outer peripheral surface of the sleeve and an inner peripheral surface of the sleeve housing to be in communication with the first circulation hole, wherein an upper portion of the second circulation hole has a larger diameter than a lower portion thereof in an axial direction.

Abstract: An electrical machine 20, 48 comprises a first stator 22 and a second stator 24 spaced from the first stator 22, at least one of the first stator 22 and the second stator 24 including a guide arrangement 26, 50. The electrical machine 20, 48 also includes a plurality of rotor elements 30, 46 located between the first stator 22 and the second stator 24 and cooperating with the guide arrangement 26, 50 for movement relative to the first stator 22 and the second stator 24. Adjacent rotor elements 30, 46 cooperate with each other so that the rotor elements 30, 46 form a rotor and at least one of the rotor elements 30, 46 includes a coupling element 32 to transfer force to or from the rotor.

Abstract: There is provided a spindle motor including: a shaft connected directly or indirectly to a base member and having a depression groove formed in a central portion of an outer peripheral surface thereof; a sleeve rotatably installed on the shaft and having a communication hole formed so as to be connected to the depression groove; and a rotor hub fixedly installed on the sleeve to thereby rotate together therewith, wherein the communication hole is inclined so that lubricating fluid may be easily injected into the depression groove, and the sleeve has a fluid storage part formed on an outer peripheral surface thereof, the fluid storage part being connected to the communication hole and temporarily storing the lubricating fluid therein.

Abstract: In a disk drive device, a magnetic recording disk is mounted on a hub. A base rotatably supports the hub via a bearing unit. The base has a ring-shaped wall that surrounds the bearing unit and that protrudes towards the hub. A laminated core is fixed to the base. The laminated core has a ring portion and twelve teeth that radially outwardly extend from the ring portion. Coils are wound around the twelve teeth. The base includes an increasing-thickness portion formed so that the less the distance between a part of the increasing-thickness portion and the ring-shaped wall is, the thicker the part of the increasing-thickness portion becomes.

Abstract: A bearing assembly for an electric motor is provided that includes a bearing having an inner race and an outer race, and a bearing float sleeve having an outer race engaging member. The outer race engaging member includes an outer surface sized for slip fit engagement with a bearing seat formed in a motor end member such that the bearing float sleeve can be displaced axially in relation to the bearing seat and an inner surface configured for engagement with the bearing outer race such that the bearing outer race is in a fixed rotational position with respect to the bearing float sleeve. The bearing float sleeve includes at least one feature operational to maintain a fixed rotational position of the bearing float sleeve with respect to the motor end member.

Abstract: There is provided a hydrodynamic bearing assembly including: a shaft; a sleeve disposed to be spaced apart from the shaft by a predetermined interval to form a bearing clearance therewith; and a thrust member installed on the shaft, wherein at least one of the shaft, the sleeve, and the thrust member is provided with a dynamic pressure groove for generating fluid dynamic pressure in a lubricating fluid provided in the bearing clearance, and one side of a portion of the dynamic pressure groove into which the lubricating fluid is introduced is provided with a pressure reduction preventing groove for suppressing a reduction in pressure generated at the time of introduction of the lubricating fluid.

Abstract: A permanent magnet machine, a rotor assembly for the machine, and a pump assembly. The permanent magnet machine includes a stator assembly including a stator core configured to generate a magnetic field and extending along a longitudinal axis with an inner surface defining a cavity and a rotor assembly including a rotor core and a rotor shaft. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further including a plurality of permanent magnets for generating a magnetic field which interacts with the stator magnetic field to produce torque. The permanent magnets configured as one of internal or surface mounted. The rotor assembly also including a plurality of retaining clips configured to retain the plurality of permanent magnets relative to the rotor core. The pump assembly including an electric submersible pump and a permanent magnet motor for driving the pump.

Abstract: A laser-welded joint structure between insulation frame and bearing cup of fan includes a base having a bearing cup and a stator having at least one insulation frame. The insulation frame includes a sleeve portion defining a bore axially extending therethrough. The sleeve portion is provided on an inner wall surface with at least one pressing section that radially projects into the bore to press a lower side against an upper end of the bearing cup and a bearing received therein. A portion of at least one lateral side of each pressing section that is in contact with the upper end of the bearing cup is melted by laser beam to form a laser-welded joint, so that the insulation frame and the bearing cup are integrally connected together at reduced manufacturing cost and have increased structural strength. A method of forming the laser-welded joint structure is also disclosed.

Abstract: The present disclosure describes a mechanical backup bearing system arrangement to work in conjunction with non-contact magnetic bearings and capable of coping with thermal expansions of the bearing components during operations. Expansions or contractions of an inner or outer race of a bearing can be compensated using particular springs providing a low profile and a proper stiffness. An electric machine system includes a rotational portion and a stationary portion. The electric machine further includes a magnetic bearing configured to support the rotational portion to rotate within the stationary portion. A mechanical back-up bearing resides in a cavity between the rotational portion and the stationary portion. A flat spring is carried by the stationary portion and abutting the back-up bearing.

Abstract: A rotary actuator for positioning a recording head in a data storage mechanism and that includes first and second cylindrical subassemblies separated by an air gap. One of the subassemblies includes a magnetically conductive core with an electrically conductive coil wrapped thereover to enable first and second current flow directions in the circuit. The other of the subassemblies includes a magnetically conductive core and at least one magnet secured thereto. Transmission of an electric current through the electrically conductive coil induces rotation of one of the subassemblies relative to the other of the subassemblies to rotate the recording head about an axis that is perpendicular to recording media on the recording head. The disclosed rotary actuator facilitates quick and accurate recording head position changes due to low inertia of the rotating subassembly as well as reduced inductance and symmetrical mass distribution of the actuator.

Abstract: A motor includes a bearing holder having a substantially cylindrical shape and a surrounding member fixed to a radial outer surface of the bearing holder. The bearing holder includes a plurality of holder protrusion portions each including a radial outer surface at least partially making contact with the surrounding member and a plurality of holder recess portions positioned radially inward of the plurality of holder protrusion portions. The plurality of holder protrusion portions and the plurality of holder recess portions are alternately arranged along a circumferential direction. A central angle of a portion of an inner circumferential surface of the surrounding member remaining out of contact with each of the plurality of holder protrusion portions is equal to or larger than a central angle of a portion of an outer circumferential surface of a bearing unit.

Abstract: A disk drive unit includes a rotor configured to rotate a disk accommodated within a disk accommodating space and set thereon, a fixed body configured to rotatably support the rotor, a fluid dynamic pressure generating part provided between the fixed body and the rotor, and a plurality of ring-shaped members, provided in an overlapping manner along a direction of a rotational axis of the rotor within a space that communicates the disk accommodating space and a gas-liquid interface of the lubricant, and covering a gap between the rotor and the fixed body.

Abstract: A stator arrangement for an electromechanical transducer is provided. The stator arrangement includes a base structure, a coil holder, a coil mounted at the coil holder; and a flexible element connecting the base structure to the coil holder flexibly relative to each other. Further, an electromechanical transducer is provided that includes the above-mentioned stator arrangement and a rotor arrangement rotatable relative to the base structure around an axial direction. Still, further, a wind turbine is provided that includes the above-mentioned electromechanical transducer as a generator.

Abstract: There is provided a spindle motor including: a base part including a base member and a lower thrust member fixedly installed on the base member; a shaft having a lower end portion fixedly installed on the base part; an upper thrust member fixedly installed on an upper end portion of the shaft; a sleeve disposed between the upper and lower thrust members and rotatably installed on the shaft; and a rotor hub fixedly installed on the sleeve to thereby rotate together therewith, wherein the sleeve includes a connection hole formed therein in order to connect an inner diameter portion thereof to an outer peripheral surface thereof.