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: 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: In a fluid dynamic pressure bearing device using ionic liquid as lubricant, a shaft member and a sleeve member are not corroded by the ionic liquid and static electricity generated is not accumulated. Aluminum with an oxide film formed on its surface is used as the material of the shaft member 11 and the sleeve member 12 and aluminum exposure portions B1, B2 are provided on the surfaces making contact with the ionic liquid, other than dynamic pressure generating grooves, of the shaft member 11 and the sleeve member 12. Accordingly, the shaft member 11 and the sleeve member 12 are kept substantially in the same electric potential through the ionic liquid.

Abstract: A method for manufacturing a bearing mechanism used in an electric motor includes (a) inserting an annular member into a substantially cylindrical closed-bottom cup member to bring a first end portion of a shaft fitted to the annular member into contact with a thermoplastic resin member arranged on an inner bottom surface of the cup member, bringing the annular member into contact with the shaft in a direction leading from an opening of the cup member to a bottom portion of the cup member, and fixing the annular member to the cup member; and (b) deforming the resin member by externally heating the bottom portion of the cup member and applying a load acting toward the bottom portion on a second end portion of the shaft. Further, an electric motor includes a rotor unit, a stator unit, and the bearing mechanism manufactured by this method.

Abstract: A method for manufacturing a bearing mechanism includes the steps of: (a) setting a position of an annular member relative to a center axis; (b) moving the annular member toward an opening of a sleeve housing through a shaft by pressing and elastically deforming a bottom portion of the sleeve housing; (c) releasing the pressing to restore the bottom portion to its original shape; and (d) fixing the annular member to the sleeve housing. Herein, the step (b) is performed by arranging the annular member within the sleeve housing, making one end portion of the shaft received in the annular member contact an inner bottom surface of the sleeve housing or with a thrust member disposed thereon, and making the annular member contact the shaft in a direction leading from the opening to the bottom portion of the sleeve housing.

Abstract: A bearing mechanism includes a cylindrical bottom-closed sleeve unit; a shaft unit radially supported by the sleeve unit via a lubricant; and an elastic thrust plate on an inner bottom surface of the sleeve unit to contact an end portion of the shaft unit at a position on a central axis to rotatably support the shaft unit. The shaft unit has a first contact portion, and the sleeve unit has a second contact portion. The contact portions are so arranged that, when a force acting from above the inner bottom surface is applied, movement of the shaft unit is restrained by the contact portions making contact with each other. Further, a distance between the contact portions prior to the force being applied is smaller than the displacement of the shaft unit at which the thrust plate gets so pressed by the shaft unit to be permanently deformed.

Abstract: A thrust plate used in a fluid dynamic pressure bearing of the present invention includes a concave portion in which a lower end portion of a shaft is accommodated. The thrust plate is immersed in a lubricant, and is disposed between the lower end portion of the shaft and a bottom-portion upper surface of a bearing housing without being fixed to the bearing housing. Accordingly, the thrust plate radially moves in accordance with the position in which the lower end portion of the shaft is in contact with the concave portion of the thrust plate. As a result, the centers of the shaft and the thrust plate motor can be aligned satisfactorily.

Abstract: A heated tool is depressed onto the upper surface of a work in process piece made from a thermoplastic or thermosetting resin to deform the work in process piece, so that a concave portion is formed. In this way, a thrust plate with the concave portion can be manufactured easily and readily. By properly choosing a tool according to the radius of curvature of the lower end of a shaft, a concave portion having an appropriate radius of curvature can be formed on the work in process piece, and a thrust plate with high wear resistance can be manufactured.

Abstract: A fluid dynamic bearing device includes a sleeve having a bearing hole into which a shaft is inserted, the sleeve rotatably supporting the shaft to make relative rotation about a center axis and a bearing housing made of a cold-rolled steel plate or a galvanized steel plate, the sleeve being received within the bearing housing. The bearing housing is filled with lubricating oil mainly composed of ester. A radial dynamic pressure bearing portion is provided between an outer circumferential surface of the shaft and an inner circumferential surface of the sleeve, the radial dynamic pressure bearing portion having radial dynamic pressure grooves for holding the lubricating oil as working fluid and for inducing a fluid dynamic pressure in the lubricating oil during the relative rotation. At least a surface region of the bearing housing remaining in contact with the lubricating oil is coated with a layer mainly composed of nickel.

Abstract: In a manufacturing method of a disk-driving spindle motor, a disc-support member includes a base portion and a positioning portion. The disc-support member is fixed to a hub member. The base portion is in contact with a lower surface of a disc. The positioning portion extends axially upwardly from the base portion, and is disposed around the center axis. The positioning portion is in contact with an inner circumferential face or an inner circumferential rim of the disc. The disc-support member is preferably made from a resin material having a cutting resistance smaller than that of a metal material from which the hub member is made.

Abstract: A bearing apparatus includes a rotating member, a fixed member opposing the rotating member and an ink-like resin material. Opposing surfaces of the rotating member and the fixed member form a bearing part and the ink-like resin material is applied to at least one of the opposing surfaces by transfer printing.

Abstract: In a spindle motor, a core includes a plurality of core plates, which are laminated one on another. The core is constituted by laminating two cores, that is, a first core and a second core, which are different from each other in shape of a surface facing to a rotor magnet. At least a part of a cogging torque generated at the second core can be cancelled by a cogging torque generated at the first core.

Abstract: A hydrodynamic bearing device comprises a shaft bush having a substantially conical inclined dynamic pressure surface around the outer circumference thereof which is relatively rotatably inserted in a bearing sleeve having a substantially conical inclined dynamic pressure surface around the inner circumference thereof. A substantially conical inclined bearing space is created in the gap between the inclined dynamic pressure surfaces of the bearing sleeve and shaft bush. Lubricant fluid is filled inside the inclined bearing space. A proper dynamic pressure generating means is formed on at least one of the inclined dynamic pressure surfaces of the shaft bush and bearing sleeve. The lubricant fluid is pressurized by the dynamic pressure generating means to generate dynamic pressure, by which the shaft bush and the bearing sleeve are relatively elevated in the radial and thrust directions so that their rotations are supported in a non-contact manner.

Abstract: In a method for manufacturing a bearing member which is made of a porous material and has dynamic pressure grooves formed by electrochemical machining, the bearing member is impregnated with liquid such as hydrosoluble liquid or water prior to electrochemical machining. Since the hydrosoluble liquid or water is retained due to capillary force in the bearing member for which electrochemical machining is to be performed, the hydrosoluble liquid or water is not replaced with an electrolyte used in the electrochemical machining. Thus, the step of removing the electrolyte after electrochemical machining can be omitted, increasing production efficiency. Moreover, the bearing member is free from a trouble of rust as the electrolyte does not remain in the bearing member. Since the hydrosoluble liquid or water exhibits excellent affinity for the electrolyte, it does not harm processing accuracy in electrochemical machining and can be easily removed after electrochemical machining.

Abstract: A fluid dynamic-pressure bearing includes a thrust dynamic-pressure bearing between a bearing member and a rotor hub and a tapered sealing portion continuous with the thrust dynamic-pressure bearing and defining a radial gap whose width gradually increases in the axial direction. A neck is formed in a passageway between the thrust dynamic-pressure bearing and a lubricating fluid/air interface maintained in the tapered sealing portion for increasing flow resistance of the lubricating fluid.

Abstract: In a spindle motor, a core includes a plurality of core plates, which are laminated one on another. The core is constituted by laminating two cores, that is, a first core and a second core, which are different from each other in shape of a surface facing to a rotor magnet. At least a part of a cogging torque generated at the second core can be cancelled by a cogging torque generated at the first core.

Abstract: An ionic liquid is utilized as the dynamic-pressure fluid charged inside a bearing space formed in the gap where an axial bushing (axial component) [21] and a bearing sleeve (bearing component) [13] oppose. Designing a dynamic-pressure bearing device is made possible virtually without having to consider such factors as how to control dynamic-pressure-fluid evaporation or how to secure electrical continuity between the axial bushing and the bearing sleeve. Owing to ionic liquids' property of not hydrolyzing, deterioration of the dynamic-pressure fluid from moisture absorption, oxidation, etc. is inhibited, yielding a dynamic-pressure bearing device with a long lifespan.

Abstract: Spindle-motor stator includes at least a first core sheet and at least one or more second core sheets located next to an end core sheet. A bent portion bent upward and a protrusion extending upward from the bent portion are formed at the forward end of the plurality of the first core sheet. Each of the plurality of teeth is wound with a conductive wire.

Abstract: A sleeve portion is inserted into a hole portion of a base bracket on which an adhesive of heat cure type is applied while a rotor portion and a stator portion are retained by a position determining jig. Then, the sleeve portion is initially affixed to the base bracket by a high frequency induction heating of an induction coil. Then, the initial affixation is cured completely in an oven. Since the adhesive of heat cure type is used, generation of outgass will be minimized and a manufacturing cost of the motor having such components will be reduced.

Abstract: In a spindle motor, a core (33) includes a plurality of core plates (34), which are laminated one on another. The core (33) is constituted by laminating two cores, that is, a first core (34a) and a second core (34b), which are different from each other in shape of a surface facing to a rotor magnet (32). At least a part of a cogging torque generated at the second core (34b) can be cancelled by a cogging torque generated at the first core (34a).