Abstract: Disclosed herein is a hydrodynamic bearing module, including: a shaft; a sleeve having the shaft rotatably and insertedly coupled thereinto and forming a micro-interval together with the shaft; oil injected in order to form a hydrodynamic bearing part between the shaft and the sleeve; a cover coupled to a lower end portion of the sleeve and sealing the oil; and a protrusion member positioned between the shaft and the cover in an axial direction of the shaft and selectively mounted on the cover or the shaft.

Abstract: There is provided a hydrodynamic bearing assembly including: a sleeve against which a shaft is supported so that an upper end of the shaft, being compressed and inserted into a hub base of a rotor case, protrudes upwardly in an axial direction; a first thrust dynamic pressure generating part formed in at least one of a protrusion and the hub base corresponding to the protrusion, the protrusion being formed at an end of the sleeve along an inner diameter direction; and a second thrust dynamic pressure generating part formed around a protruding end portion of the sleeve, the protruding end portion facing an upper portion of a stopper part in the axial direction and the stopper part rotating together with the rotor case. Also, an oil sealing part has an oil interface between an outer circumferential surface of the sleeve along an outer diameter direction and an inner surface of the stopper part.

Abstract: There is provided a hard disk drive including: a bottom plate including a disk rotating by a motor; and a cover having a first wall member formed thereon, the first wall member inducing an airflow generated at the time of rotation of the disk.

Abstract: There are provided an apparatus for clamping a disk and a motor assembly having the same. The apparatus for clamping a disk according to the present invention includes an apparatus for clamping a disk, including: a rotor case jointed with an outer peripheral surface of a shaft and rotating together with the shaft; a flange part including a disk mounting surface formed at a radial outer side of the rotor case and formed to be inclined as the disk mounting surface is toward the radial outer side; and a clamping member pressing and clamping the disk to the rotor case, wherein an inclination of the disk mounting surface of the flange part is changed depending on the position of the pressing point to the disk of the clamping member.

Abstract: There is provided a spindle motor including: a sleeve rotatably supporting a shaft; a cover member installed on a lower end portion of the sleeve; and a bonding member disposed between the sleeve and the cover member such that the cover member is installed on the sleeve and formed of an anisotropic conductive material.

Abstract: There is provided a hard disk drive including: a bottom plate including a disk rotating by a motor; and a cover having a first wall member formed thereon, the first wall member inducing an airflow generated at the time of rotation of the disk.

Abstract: There is provided a spindle motor including: a hub operating together with a shaft and including a magnet; a base coupled to a sleeve supporting the shaft and including a core having a coil wound therearound, the coil generating rotational driving force; and a shielding part provided on the magnet and blocking magnetic flux introduced from the magnet into the base to thereby increase magnetic flux density between the magnet and the core, wherein the shaft and the hub rotate while descending via oil when power is applied to the coil.

Abstract: A hydrodynamic bearing assembly includes a sleeve rotatably supporting a shaft, a thrust plate housing portion extending to an upper side of the sleeve in an axial direction so as to house a thrust plate, and a stopper ring housing portion stepped in an upper side of the thrust plate housing portion in the axial direction and housing a stopper ring for fixing the thrust plate. The stopper ring protrudes from the stopper ring housing portion such that an outer circumferential surface of the stopper ring has a larger height than an inner circumferential surface of the stopper ring housing portion.

Abstract: Disclosed herein is a highly-durable electrode tool for electrochemical machining, which can prevent the corrosion and abrasion of a conductive pattern at the time of electrochemical machining for forming dynamic pressure-generating grooves of a fluid dynamic bearing, and a method of manufacturing the same. The electrode tool for electrochemical machining includes: an electrode substrate on which a conductive pattern is formed to have protrusions corresponding to the fine grooves and to which negative current is applied; a nonconductive insulating layer, covering an entire top surface of the electrode substrate excluding the conductive pattern; and a conductive layer, which is formed on the conductive pattern to protect the conductive pattern, and a top surface of which is the same height as a top surface of the nonconductive insulating layer.

Abstract: Disclosed herein is a method of manufacturing a hydrodynamic bearing in which a metal bearing made of sintered metal powder is internally subjected to chemical etching, to form hydrodynamic pressure grooves thereon, thus assuring a high-precision and reliable hydrodynamic bearing. The method includes: compressing metal powder that is a raw material of the bearing in a press unit, and sintering the compressed metal powder at a predetermined temperature, thus preparing a sintered bearing; removing foreign substances adhering to the sintered bearing through a deburring process, and pressing the sintered bearing into a desired shape; forming a hydrodynamic groove, configured to generate hydrodynamic pressure, on an internal surface of the shaped bearing using chemical etching; and conducting a post treatment of cleaning the bearing including the hydrodynamic grooves thereon and drying the bearing.

Abstract: There are provided an apparatus for clamping a disk and a motor assembly having the same. The apparatus for clamping a disk according to the present invention includes an apparatus for clamping a disk, including: a rotor case jointed with an outer peripheral surface of a shaft and rotating together with the shaft; a flange part including a disk mounting surface formed at a radial outer side of the rotor case and formed to be inclined as the disk mounting surface is toward the radial outer side; and a clamping member pressing and clamping the disk to the rotor case, wherein an inclination of the disk mounting surface of the flange part is changed depending on the position of the pressing point to the disk of the clamping member.

Abstract: There is provided a hydrodynamic bearing assembly including: a sleeve against which a shaft is supported so that an upper end of the shaft, being compressed and inserted into a hub base of a rotor case, protrudes upwardly in an axial direction; a first thrust dynamic pressure generating part formed in at least one of a protrusion and the hub base corresponding to the protrusion, the protrusion being formed at an end of the sleeve along an inner diameter direction; and a second thrust dynamic pressure generating part formed around a protruding end portion of the sleeve, the protruding end portion facing an upper portion of a stopper part in the axial direction and the stopper part rotating together with the rotor case. Also, an oil sealing part has an oil interface between an outer circumferential surface of the sleeve along an outer diameter direction and an inner surface of the stopper part.

Abstract: A hydrodynamic bearing assembly includes a sleeve rotatably supporting a shaft, a thrust plate housing portion extending to an upper side of the sleeve in an axial direction so as to house a thrust plate, and a stopper ring housing portion stepped in an upper side of the thrust plate housing portion in the axial direction and housing a stopper ring for fixing the thrust plate. The stopper ring protrudes from the stopper ring housing portion such that an outer circumferential surface of the stopper ring has a larger height than an inner circumferential surface of the stopper ring housing portion.

Abstract: Disclosed herein is a highly-durable electrode tool for electrochemical machining, which can prevent the corrosion and abrasion of a conductive pattern at the time of electrochemical machining for forming dynamic pressure-generating grooves of a fluid dynamic bearing, and a method of manufacturing the same. The electrode tool for electrochemical machining includes: an electrode substrate on which a conductive pattern is formed to have protrusions corresponding to the fine grooves and to which negative current is applied; a nonconductive insulating layer, covering an entire top surface of the electrode substrate excluding the conductive pattern; and a conductive layer, which is formed on the conductive pattern to protect the conductive pattern, and a top surface of which is the same height as a top surface of the nonconductive insulating layer.

Abstract: Disclosed is an internal weight type vertical vibrator including: a housing; a magnetic circuit unit placed in the internal space of the housing, and comprising a magnet perpendicularly placed and a yoke for fixedly receiving the magnet therein for generating a magnetic field; spring members provided with upper ends fixed to the housing and lower ends fixed to the magnetic circuit unit for vertically; a vibrating unit placed in the yoke so that the outer surface of the vibrating unit is surrounded by the yoke, comprising the weight having a hollow cylindrical structure provided with a central hole, into which the magnet is inserted; and a vibration-generating coil placed just below the magnetic circuit unit so that the vibration-generating coil is interlinked with the magnetic field of the magnet for allowing current supplied from the outside to flow in one direction therethrough.

Abstract: A vertical vibrator is disclosed. The vibrator comprises a casing, a magnetic field part including a yoke and a magnet fixed to an inner surface of the yoke, a spring member fixed at one end to the casing and at the other end to the magnetic field part, a vibration part having a weight integrally mounted to the magnetic field part and vibrating together with the magnetic field part through the spring member, a vibration coil located below the magnetic field part for generating an electric field, and a magnetic fluid applied to an upper surface of the spring member corresponding to the magnet and fixed in position by a magnetic flux. The vibrator absorbs contact noise and impact caused by contact between the vibration part and the other members while ensuring convenient and appropriate positioning of the magnetic fluid, thereby having an extended life span.

Abstract: The invention relates to a structure of a spindle motor. The spindle motor comprises a housing assembly; a shaft fixed to the center portion of the housing assembly, a stator secured to the housing assembly around the shaft, a spindle hub having an inner cylindrical portion and an outer cylindrical portion, a rotor magnet secured to a circumferential inner surface of the outer cylindrical portion of the spindle hub, and a pair of bearings provided around the shaft in the inner cylindrical portion; wherein the spindle hub has a flat plate portion formed in the center part thereof and the flat plate portion has an opening through which the shaft is passed, thereby the flat plate portion functions as a labyrinth seal.

Abstract: A housing for spindle motor with low height has an improved structure to facilitate the chucking by previously forming a chucking groove first formed into a corner part along the inside of a chucking portion, and its fabricating process is improved to simultaneously fabricate important parts since the chucking is facilitated as such. Here, a shallow annular groove with an optional width is previously formed along the innermost side of the bottom plane of a flange part to fabricated the bottom plane of the flange part at a time during a precise fabricating process of cutting the parts requiring precision tolerance free from a chuck of a cutter tool that grips an outer circumference of a disc part. Its fabricating is performed by chucking a cylinder part to expose the bottom plane of the flange part, i.e.

Abstract: The present invention relates to a spindle motor used in a hard disc drive or a magnetic recording/reproducing apparatus, wherein air discharge guiding arrangement prevents foreign matter such as lubricating particles and dust scattered in the bearings of the spindle motor from flowing into a clean space by guiding air flows in the direction opposite to the clean space, without using any separate hermetic seal.