Abstract: A rotating body for a fluid dynamic bearing used for rotating a recording disk that has been mounted therein include: a rotating shaft portion in which a cylindrical portion that serves as a rotating shaft and a protruding portion extended radially outward from one end of the cylindrical portion are formed integrally with each other; and a hub that is to be connected to the end portion near to the outer circumference of the protruding portion and that has a mounting seat portion on which the recording disk is to be mounted.

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 brushless motor is provided. A stator core has a plurality of teeth extending radially from an annular portion of the stator core. The number of the teeth is an integral multiple of the number of coil-drive phases. Coil relief holes for allowing coils to enter are formed on the motor base. The number of the coil relief holes is less than the number of the teeth by the number of the coil-drive phases multiplied by N (N is a natural number). The number of turns of the motor-drive coil wound around one of the teeth corresponding to a portion of the motor base where the coil relief hole is not formed is set to less than that corresponding to a portion of the motor base where the coil relief hole is formed.

Abstract: In a rotating machine, a recording disk is mounted on a hub. A base rotatably supports the hub through a bearing unit. A core is fixed to the base and includes an annular portion and a salient pole radially extending therefrom. A coil is formed by winding a wire around the salient pole. The wire is pulled out to the back surface of the base through a pull-out hole provided in the base and soldered to a wiring.

Abstract: A recording disk is to be mounted on a hub. A base rotatably supports the hub through a bearing. A stator core is fixed to the base and includes an annular portion and a salient pole extending radially therefrom. A magnet faces the salient pole radially and is rotated with the hub. The magnet has a plurality of magnetic poles in the circumferential direction such that each of the plurality of magnetic poles faces the salient pole. The salient pole includes a rod-shaped body around which a wire is wound and a tooth portion that is provided radially outside the rod-shaped body and extends circumferentially. The circumferential end located at the end in the circumferential direction of the tooth portion is located radially inside a circumscribed circle passing through the tip located at the radially outermost end of the tooth portion.

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 disk drive device includes a base member; a hub on which a recording disk is placed; a bearing unit arranged on the base member for rotatably supporting the hub; and a spindle drive unit for rotationally driving the hub, wherein the spindle drive unit includes a stator core having salient poles, a coil wound around each of the salient poles, and a magnet having a plurality of magnetic poles arranged in a circumferential direction opposed to the salient poles, the hub includes an outer cylindrical portion formed of a magnetic material and engaged with an inner periphery of the recording disk, and an inner cylindrical portion fixing an outer periphery of the magnet, the number of magnetic poles is an even number in a range of 10 to 16, and the number of salient poles is a multiple of 3 in a range of 12 to 24.

Abstract: A rotary device according to an aspect of the invention includes: a sleeve having an inner cylindrical surface, a first end portion and a second end portion at respective ends of the inner cylindrical surface; a shaft that is accommodated in the inner cylindrical surface in a manner rotatable relative to the inner cylindrical surface; a fluid present in a space between the shaft and the sleeve; a first pump portion formed in a middle portion of the inner cylindrical surface and configured to cause the fluid to flow toward the first end portion by the relative rotation of the shaft and the sleeve; a first radial narrow gap formed at a region of the inner cylindrical surface on a side of the first end portion with respect to the first pump portion; and a first circulation path communicated with the first pump portion.

Abstract: A production method of a disk drive device includes: an assembling process of assembling a subassembly by incorporating at least a bearing unit in a hub in a clean room; a pouring process of pouring a lubricant in the bearing unit; a cleaning-liquid discharging process of discharging a cleaning liquid to the hub; a cleaning-liquid intake process of taking in the cleaning liquid discharged to the hub; and a sealing process of sealing the subassembly in a seal-material.

Abstract: In a disk drive device, a hub has an outer circumferential wall portion configured to hold a recording disk. A base member has a cylindrical portion, whose central axis is the rotation axis of the hub, on a surface on the side of the hub. A fluid dynamic bearing holds a lubricant and rotatably supports the hub relative to the base member. A ring-shaped attraction plate including a magnetic material is fixed to the base member and faces a magnet in the axial direction. The outer circumferential wall portion is configured such that the outer circumferential wall portion surrounds the attraction plate and that the range of the outer circumferential wall portion in the axial direction overlaps with the range of the attraction plate in the axial direction.

Abstract: A disk drive device comprises a hub on which a magnetic recording disk is to be mounted; a base rotatably supporting the hub through a bearing unit; a sintered core fixed to the base, the sintered core having a ring portion and nine teeth that extend radially from the ring portion; coils wound around nine teeth; and a cylindrical magnet fixed to the hub. The sintered core is formed by heat-treating an iron powder. At least one of (a) the surfaces of particles of the iron powder and (b) the surfaces of the sintered core is insulated.

Abstract: A thrust dynamic pressure pattern is marked on a rotating member or fixed member set on a rest table. A pressure for marking is applied to a member to be marked in a cycle of applying and releasing the pressure, and a supplemental force for keeping the member to be marked, still is separately applied. According to the present embodiment, a rotating device can be provided that narrows down a bearing gap and improves the efficiency of raking up a lubricant so as to increase the dynamic pressure by reducing the deformation of the shape of the protrusions of a thrust dynamic pressure pattern and the variation in the height of the protrusions when forming the thrust dynamic pressure pattern in a method of producing a rotating device.

Abstract: A disk drive device has a hub so configured as to place and hold recording disks. Where the non-rotating eigenfrequency of resonance in a secondary rocking mode with the recording disks placed on the hub is defined to be F0 (Hz) and the rotational frequency of the hub is defined to be N (Hz), an extending part of the hub and a second cylinder part of the hub are formed such that the radial dimension of the extending part is smaller than the axial dimension of the second external cylinder part to satisfy to a relation F0>N·(3·P+2).

Abstract: A bearing unit includes a shaft and a hub as a conductive rotating body that supports a recording disk. Also, the bearing unit includes a conductive resin housing configured to surround at least part of the shaft to support the shaft and to be able to conduct electricity to the recording disk via the shaft. The conductive resin housing includes a conductive adhesive to be applied to secure conduction with the base housing. The conductive resin housing has an exposed portion where the inner layer of the conductive resin housing is exposed, at a position to which the conductive adhesive is applied.

Abstract: A bearing lubricant includes a base oil containing an ester compound consisting of 2-ethyl-2-methyl-1,3-propanediol and at least one of carboxylic acids having 5 to 12 carbon atoms, the ester compound being represented by the following formula (1), in which the base oil has a kinetic viscosity at approximately 40° C. of approximately 7 to 15 mPa, and has a pour point of approximately ?60° C. or less: where R1 and R2 represent hydrocarbon groups having 4 to 11 carbon atoms.

Abstract: A disk drive device includes: a hub on which a recording disk is to be mounted; a base member; a bearing unit configured to support the hub in a manner in which the hub can be relatively rotated with respect to the base member; an extended annular groove portion provided in part of the hub around the rotational axis of the hub; and a weight member that is installed in the extended annular groove portion to adjust a rotational balance when the recording disk is being rotated with the hub. The weight member has a fixing mechanism that is slidable, when installed, in the direction of the extended annular groove portion and that can substantially maintain a stopped state at a fixing position.

Abstract: In A disk drive device, a magnetic recording disk is to be mounted on a hub. A base plate rotatably supports the hub through a bearing unit. A projecting portion is formed on the upper surface of the base plate. The projecting portion has a cylindrical side surface, the center of which being along the rotational axis of the motor. A laminated core is formed by laminating eight magnetic steel sheets and has a ring portion and a plurality of teeth that extend radially from the ring portion. The disk drive device has a tubular vibration-deadening ring. The outer surface of the vibration-deadening ring is press-fitted into the ring portion, and the inner surface is fixed to the side surface of the projecting portion. The outer surface of the vibration-deadening ring is pressed against the ring portion at least at a position closer, in the direction along the rotational axis of the motor, to the upper surface of the laminated core than to the lower surface of the laminated core.

Abstract: A bearing device is composed of a shaft, a sleeve for supporting the shaft so as to be rotatable freely and a housing having a through hole into which the sleeve is inserted. A circumferential groove that extends in a circumferential direction is formed on either one surface of an outer circumferential surface of the sleeve and an inner circumferential surface of the housing. An axial groove that extends approximately in parallel to a central axis of the sleeve is formed on either one surface of the outer circumferential surface of the sleeve and the inner circumferential surface of the housing. The outer circumferential surface of the sleeve is glued to the inner circumferential surface of the housing by adhesive that intervenes in both the circumferential groove and the axial groove.

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: A disk drive device includes: a hub on which a recording disk is to be mounted; a shaft; a sleeve configured to house the shaft and to be rotatable relatively with respect to the shaft; a radial space portion formed between the inner circumferential surface of the sleeve and the outer circumferential surface of the shaft; a radial dynamic pressure generating portion configured to generate radial dynamic pressure between at least part of the inner circumferential surface of the sleeve and the outer circumferential surface of the shaft in the radial space portion; and lubricant. The axial length of the radial dynamic pressure generating portion is formed to be longer than the diameter of the radial dynamic pressure generating portion such that radial dynamic pressure, which is defined with the axial length of the radial dynamic pressure generating portion and the diameter thereof being parameters, is greater than or equal to a predetermined minimum reference value.