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: 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: 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: 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 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: 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: 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: 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 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: 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 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: 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 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: 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: 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.

Abstract: A motor includes a base, a rotor and a stator. The base includes a shaft tube having an open end and a closed end. A shaft supporting assembly is received in the shaft tube and includes a top portion. The rotor includes a shaft rotatable about a longitudinal axis, and the shaft includes a retaining groove. The stator includes a limiting member having a distal end. The limiting member defines an opening through which the shaft extends. The limiting member further includes a bottom facing the shaft supporting assembly. A gap and a supporting member are formed between the bottom and the top portion. The supporting member is closer to the shaft tube than to the shaft, and the gap is closer to the shaft than to the shaft tube.

Abstract: This disclosure discloses a rotating electrical machine that is integrally formed with a reduction device having an input shaft and an output shaft and employs one of a field system and an armature as a rotor and the other of the field system and the armature as a stator, including a rotating shaft to which the rotor is fixed and that is coaxially connected to the input shaft of the reduction device, and a bearing support member configured to support bearings that rotatably support the input shaft of the reduction device, wherein the stator is provided to the bearing support member.

Abstract: Disclosed herein is a motor structure with reduced rotation resistance of a bearing. The motor structure according to the preferred embodiment of the present invention includes: a fixing body, a shaft fixed to the fixing body, a bearing rotatably fitted on the shaft, a rotating body fixed to an outer side of the bearing and rotated by electromagnetic force, a case fixed to the fixing body and having the shaft, the bearing, and the rotating body accommodated in an inner space thereof, and a washer fixed to a top inside of the case so as to be interposed between the top inside of the case and a top surface of the bearing and contacting a part of the top area of the bearing.

Abstract: A wave washer is used for a shaft supporting device of an electric power steering system. The wave washer has an annular portion and six outward protrusions. The annular portion has first protrusions that protrude in a first axial direction and second protrusions that are formed so as to continuous with the first protrusions and that protrude in a second axial direction. Each outward protrusion protrudes from an outer periphery of the annular portion in a radially outward direction of the radial direction of the annular portion.

Abstract: There are provided a spindle motor including a lower thrust member fixed to a base member; and a shaft fixed to the lower thrust member, wherein the lower thrust member includes a fitting protrusion protruding upwardly in the axial direction and fitted into a fixing groove formed in a lower end of the shaft so as to be depressed upwardly in the axial direction, a thrust bearing surface forming a thrust bearing between the thrust bearing surface and a lower surface of the sleeve, and an extension part protruding from an outer edge of the lower thrust member in a radial direction upwardly in the axial direction to form a liquid-vapor interface between the extension part and an outer surface of the sleeve while enclosing the sleeve, and the thrust bearing surface has inner and outer concave parts depressed in one of inner and outer diameter directions thereof, respectively.

Abstract: The disk drive device includes a base member with a first upper surface and a second lower surface, a hub, a bearing unit arranged on the base member that rotatably supports the hub, a spindle drive unit that drives the hub to rotate, and a wiring member arranged on the second surface of the base member. The spindle drive unit includes a stator core having a salient pole with coil wound around, and a magnet opposed thereto. The base member includes a wire hole through which a wire is placed, with a first opening on the first surface and a second opening on the second surface. A concaved area on the second surface includes a lower slope, axially between the concaved area and the second opening on which a wiring member is arranged. The wire is connected to the wiring member, radially outside of an outer diameter of the magnet.

Abstract: A linear actuator displaces a relative position between a guide rail and a slide table, which is arranged in confronting relation to the guide rail. Projections are formed on opposite end sides of the guide rail, the projections extending along a direction of displacement and projecting toward the slide table. The slide table is disposed between the projections on the opposite end sides of the guide rail, with rigid balls being interposed therebetween. Guide grooves and guide grooves, which rollably support the balls, are provided on the projections on the opposite end sides of the guide rail and on the slide table. The guide grooves and the guide grooves apply, on the balls, a pressure caused by a magnetic attractive force of permanent magnets.

Abstract: A motor includes a shaft supported by upper and lower bearings and rotatable about an axis; a rotor magnet fixed to the shaft; a stator arranged radially outside and opposite to the rotor magnet with a gap therebetween; an upper bracket holding the upper bearing; and a lower bracket holding the lower bearing. The upper bracket includes an upper cylindrical cover press fitted to a stator core from above, an upper bearing holding portion, and a top plate portion arranged to join the upper cylindrical cover and the upper bearing holding portion. The lower bracket includes a lower cylindrical cover press fitted to the stator core from below, a lower bearing holding portion, and a bottom plate portion arranged to join the lower cylindrical cover and the lower bearing holding portion. Each of the upper and lower brackets is fixed to the stator core through press fitting.

Abstract: A spindle motor includes a stationary portion with a shaft, a circular plate portion, a wall portion, and a plate portion. The plate portion has a flat plate portion and an annular convex portion. The sleeve includes an annular portion, an outer side cylindrical portion, and an inner side cylindrical portion. The inner side cylindrical portion and an upper radial dynamic pressure groove array are superimposed in a radial direction. The upper radial dynamic pressure groove array includes a plurality of upper spiral grooves that is inclined in one direction with respect to an axial direction and a plurality of lower spiral grooves that is inclined in another direction opposite to the one direction. A lower end of the upper spiral grooves is positioned farther on an upper side than an upper surface of the annular portion.

Abstract: A permanent magnet rotor shaft assembly for a high speed electrical machine provides a permanent magnet cylindrical core having a longitudinal axis, the cylindrical core being axially compressed by first and second end shafts and being radially compressed by a sleeve made of a non-magnetic high strength metal. At least one of the first and second end shafts includes, facing the cylindrical core, a central shoulder head that cooperates with a mating central recess made in a central portion of a front face of the cylindrical core. An easy concentric alignment of the first and second end shafts with the permanent magnet cylindrical core is allowed while inserting the sleeve and the stiffness of the assembled set is enhanced.

Abstract: Provided is a rotor structure of a rotary electric machine, which is easily adaptable to offer a wide variety of products. The rotor structure of a rotary electric machine includes at least: a rotor shaft (3); a rotor core including a first rotor core section (15) and a second rotor core section (17); a boss section (9); and a pressurizing section. The second rotor core section and the boss section are arranged on an outer circumference of the rotor shaft. The first rotor core section is arranged on an outer circumference of the boss section. The pressurizing section is positioned on an axially outer side of the rotor core. The second rotor core section is pressurized by an abutment surface of the boss section. The first rotor core section arranged on the boss section is pressurized by the pressurizing section.

Abstract: A bearing mechanism includes a stationary portion and a rotating portion. The stationary portion includes a shaft portion and a plate portion. The rotating portion includes a sleeve including an annular portion, a cylindrical portion, an annular bottom surface, and a first communication hole. The rotating portion includes a ring member arranged to cover at least a portion of an opening of the first communication hole, and faces the plate portion via a first gap. A pumping groove array is disposed in the plate portion or the ring member. A second communication hole is disposed between the ring member and the annular bottom surface, and connected to the first communication hole. At least a portion of the opening of the second communication hole is positioned on a farther radial direction inner side than the pumping groove array.

Abstract: A rotor unit for a brushless direct current motor (BLDC motor) comprises a main body integrally formed with a rotor shaft and an annular ring magnet mounted on the main body. The annular magnet comprises an anisotropic hard ferrite and is laterally magnetized. The rotary shaft and the main body of the rotor unit may be formed from one plastic material. The rotor unit is supported within the BLDC motor via self-lubricating bearing seats.

Abstract: A spindle motor includes a stationary portion and a rotating portion. The stationary portion includes a shaft and the rotating portion includes a sleeve portion, a hub, a magnet, and a cap. The sleeve portion is arranged opposite to the shaft. The hub is made of metal, and includes a top plate portion extending radially outward from the sleeve portion, and an outer tubular portion extending downward from an outer edge of the top plate portion. The magnet is fixed to the outer tubular portion and is arranged opposite to the stator. The cap is made of metal, and includes an annular plate-shaped portion fixed to an upper surface of the top plate portion. The magnet has a coefficient of thermal expansion greater than that of the hub. The cap has a coefficient of thermal expansion greater than that of both the hub and the magnet.

Abstract: Systems and methods for rotor bearings that enable improved oil circulation, wherein axial grooves are formed in the outer periphery of each bearing to form channels that allow axial flow of oil through the channels. Each bearing includes a collar, a sleeve and an interference ring. The collar has a bore through its center in which a rotatable sleeve is positioned. The outer periphery of the collar has a circumferential groove and at least one axial groove that extends from one face of the collar to the other. An axially permeable interference ring positioned within the circumferential groove extends radially outward from the groove beyond the outer periphery of the collar. The interference ring (e.g., a looped coil spring) allows fluid in the axial groove to flow through the interference ring. The axial groove may have a different depth than the circumferential groove.

Abstract: A disk-rotating motor includes a rotor section including a rotor magnet attached to a rotor frame and a shaft fixed to a center of the rotor frame, and a stator section including a shaft-bearing which bears the shaft, wherein the stator section includes the shaft-bearing, a shaft-bearing housing which holds the shaft-bearing, a thrust plate which bears the shaft in an axis direction, a stator core which is arranged to face the rotor magnet and provided with wire-winding, a core holder which holds the stator core, and a bracket which holds the shaft-bearing housing. The bracket has a projecting part which fixes the shaft-bearing at a central part thereof, an inner diameter part of the shaft-bearing is press-fitted to be tightened to the projecting part, and an outer diameter part of the shaft-bearing housing is adhered to be tightened to an inner diameter part of the core holder.

Abstract: A method and system for reducing bearing failure in a rotating electrical device includes installing a magnetic core around the rotor shaft between the rotor and the bearing. The magnetic core creates an electrical impedance which reduces the current which flows through the bearings, and therefore reduces bearing failure.

Abstract: A motor includes a stator integrally molded together with a stator member, which includes a stator iron-core wound with a winding, by insulating resin, a rotor mounted on a shaft as a center and confronting the stator, two bearings supporting the shaft rotatably, brackets fixing the bearings, and a drive circuit board including a drive circuit which supplies an electric current to the winding and drives the rotor. Either one of the two bearings includes an outer ring and an inner ring both of which are electrically insulated from each other.

Abstract: A spindle motor includes an upper bearing portion and a lower bearing portion each of which is inclined with respect to a central axis. The upper bearing portion includes an upper dynamic pressure generating groove defined in at least one of an upper outer circumferential surface of a shaft portion and an upper inner circumferential surface of a sleeve. The lower bearing portion includes a lower dynamic pressure generating groove defined in at least one of a lower outer circumferential surface of the shaft portion and a lower inner circumferential surface of the sleeve. The radial distance between a lower end portion of the upper dynamic pressure generating groove and the central axis is shorter than the radial distance between an upper end portion of the lower dynamic pressure generating groove and the central axis.

Abstract: A spindle motor includes a stationary portion and a rotating portion. The stationary portion includes a shaft, a first cup portion. The first cup portion includes a circular plate member and an annular member. The rotating portion includes an annular concave portion that accommodates at least a lower end portion of the annular member. A lubricant is interposed in a gap between a surface of a stationary portion and a surface of the rotating portion. The shaft, the rotating portion, and the lubricant define a fluid dynamic pressure bearing. A connection gap that reaches an inner side of the first cup portion from an outer circumferential surface of the first cup portion is configured between the circular plate member and the annular member. At least a portion of the connection gap is filled with an adhesive.

Abstract: A method of and a device for protecting an electric motor (4) in a pod unit (1) for propulsion of marine vessels against shaft bending shocks when the blades (2) of the pod propeller hit ice blocks or other hard objects, said motor (4) having a drive shaft (3), a rotor (41) and a stator (42), said shocks tending to momentarily bend the drive shaft (3) to such an extent that the rotor (41) will come into contact with the stator (42). In accordance with the present invention, the rotor (41) is prevented from coming in detrimental contact with the stator (42) by providing at least two members (61, 62), which together form a radial plain bearing (6) having mating arcuate bearing surfaces (611 and 621, respectively), which during normal operation of the motor (4) are spaced from one another by a gap and come in contact with one another only at extreme loads with short durations.

Abstract: A spindle motor comprises a turntable, on which a disc is loaded, and a motor which rotates the turntable, wherein a top face plate of a magnetic body rotor case, which rotates united with a rotational shaft of the motor, serves as the turntable. A centering member that guides the inner edge of the disc so as to be concentric with the rotational shaft is disposed on the top face plate of the rotor case and a clamping magnet is disposed in a through-opening on the interior of the centering member and is in contact with the top face plate of the rotor case.

Abstract: An axial flux electric machine and associated method of use that includes a shaft, a rotor attached to the shaft, a plurality of permanent magnets positioned underneath the rotor, an electrical winding positioned below the plurality of permanent magnets, a stator that encircles the shaft that is located below the rotor, a first bearing assembly located below the stator and encircling the shaft of the rotor, a second bearing assembly located below the first bearing assembly and encircling the shaft, and a spring mechanism, located between the first bearing assembly and the second bearing assembly, to distribute load placed on the shaft between the first bearing assembly and the second bearing assembly.

Abstract: A spindle motor is provided, the motor comprising: a base plate, a PCB on the base plate, a bearing assembly arranged on the base plate, a stator coupled to a periphery of the bearing assembly, a rotor rotationally coupled to the bearing assembly, the rotor including a yoke and a magnet, and a rotation shaft rotationally coupled to the bearing assembly. The base plate includes a planar portion and a protruding portion arranged along with a periphery of the yoke, the protruding portion being apart from the yoke. The base plate is partially covered with the PCB in a region where the stator is arranged. And, a height from the planar portion to an upper surface of the protruding portion is smaller than a height from the planar portion to a lower surface of the periphery of the yoke.

Abstract: A spindle motor is provided, the motor including: a base plate; a PCB Printed Circuit Board arranged on an upper surface of the base plate; a bearing assembly coupled to the base plate; a stator coupled to a periphery of the bearing assembly; and a rotor rotationally coupled to the bearing assembly, wherein the base plate is formed with a foreign object inflow prevention fence to inhibit inflow of foreign objects into the stator and the base plate.

Abstract: A disk drive device includes a chassis, a top cover fixed to a chassis, a rotating body on which a disk retained in a disk retaining space formed between the chassis and the top cover is to be mounted, and a bearing body that supports the rotating body in a freely rotatable manner relative to the chassis. The bearing body has a lubricant applied in a predetermined area, and a capturer that captures the vaporized lubricant from the gas-liquid interface is provided in a space in communication with the disk retaining space from the gas-liquid interface of the lubricant.

Abstract: A brushless motor includes a stator molded integrally with a resin having a fixing member including a stator iron core and a winding wound thereon, a rotor of a disk-like iron core holding a ferrite resin magnet in a circumferential direction, the rotor arranged to face the stator about a shaft, a bearing rotatably supporting the shaft, and conductive brackets fixing the bearing. The brackets are electrically connected to each other with a conducting pin in the stator.

Abstract: There is provided a rotating member for a motor, the rotating member including: a hub coupled to a shaft system of the motor and rotating together therewith; a main wall portion protruding from one surface of the hub and allowing oil to be sealed between the main wall portion and a sleeve supporting the shaft system; and a pumping portion formed in a lower surface of the main wall portion and generating fluid pressure for preventing a leakage of the oil.

Abstract: There is provided a spindle motor including: a shaft including a body portion having a fixing recess formed on a lower portion thereof, a flange portion extending in an outer radial direction from an upper portion of the body portion, and a first insertion portion extending downwardly from the flange portion in an axial direction; a lower thrust member including a fixed portion inserted into the fixing recess, a disk portion extending from the fixed portion in an outer radial direction, and first and second protrusion portions extending from the disk portion in the axial direction; a base member coupled to the second protrusion portion; and a rotating member forming a bearing clearance with the shaft and provided to be rotatable with respect to the shaft.

Abstract: A first capillary seal portion is positioned on a radially outer side of a bearing portion. A second capillary seal portion is positioned higher in an axial direction than the bearing portion and further on radially inner side than the first capillary seal portion. A seal cap covers a portion of an opening of the first capillary seal portion and a portion of an opening of the second capillary seal portion. The maximum width of a first gap between the outer circumferential surface of the shaft and an inner circumferential surface of the seal cap in a radial direction and the maximum width of a second gap between an upper surface of the sleeve portion and a lower surface of the seal cap in an axial direction is smaller than the maximum width of the opening of the first capillary seal portion.

Abstract: A motor includes a base, a stator unit and a rotor. The base includes a shaft tube receiving a sleeve bearing and a positioning member. The positioning member positions the sleeve bearing and includes a hole having a minimal diameter. The stator unit is arranged on the base. The rotor includes a shaft and a permanent magnet. The shaft extends through the hole of the positioning member and rotatably couples with the sleeve bearing. An air gap is formed between the permanent magnet and the stator unit. The shaft has a maximal diameter, and the minimal diameter of the hole of the positioning member is larger than 1.05 times of the maximal diameter of the shaft but is smaller than or equal to two times of the maximal diameter of the shaft.

Abstract: Control over an electric motor is especially critical in large drilling rigs and a means of accurately and quickly measuring the speed of the rotor of an electric motor and correlating that information with other real-time information has been hampered by the failure of the prior art to attach optical encoders to electric motors with precision. The present device attaches to arbor of a cap on the end of the rotor which provides a centralized and sealed shaft extending through a covering plate on the end of the motor and directly attaching to an optical encoder.

Abstract: The invention relates to a spindle motor having a fluid dynamic bearing system comprising axial and radial bearings that contains a rotor component (14) which encloses a stationary shaft (12), which in turn is connected at both its ends to axially aligned bearing parts (16; 18) that are fashioned such that they form capillary sealing gaps (32; 34), a recirculation channel (28) filled with bearing fluid that connects the remote regions of the bearing to each other, and an electromagnetic drive system (42, 44) for driving the rotor component.