Abstract: In a hydrodynamic bearing according to the present invention a fixed shaft has different diameter sizes by positions so that overflow or splashing of lubricant out of the apparatus is prevented due to a centrifugal force during high-speed rotation, and lubricant reservoirs are provided in narrower clearances and in wider clearances so that the lubricant is induced to move toward lubricant reservoirs in narrower clearances due to surface tension while the hydrodynamic bearing is in stop, therefore overflow of the lubricant is prevented at the time of starting up.

Abstract: The invention has an object to prevent discharge of foreign matters into an inner space of a casing and to improve movement stability and reliability of the disk drive. A sleeve with one end closed is connected to a front end of a shaft supported at its proximal to a base on a fixed side, a plurality of hydro dynamic pressure generating grooves are formed on at least one of an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve opposite the outer peripheral surface, a through hole communicating with the outside of the base is formed to extend from the front end to the proximal end of the shaft, and the through hole is provided with an air vent for adjusting a pressure between the shaft and the sleeve so that the amount of air to be discharged to the outside is adjusted and the sleeve is rotated in a contactless fashion with the shaft. Foreign matters are carried in a gas passing through the air vent and guided to the outside through the through hole.

Abstract: It is an object of the present invention to provide a hydrodynamic bearing which is highly reliable and capable of preventing a lubricant contained therein from flowing out of the bearing. In the hydrodynamic bearing, lower and upper end portions of a stationary shaft are properly spaced from a sleeve and a thrust plate, respectively, and an air channel is provided inside the stationary shaft with one end thereof opening to a space defined between an outer circumferential portion of the stationary shaft and the sleeve and with the other end thereof communicating with the outside. Thus, the hydrodynamic bearing has a highly reliable construction which can assuredly prevent the flow-out of the lubricant.

Abstract: A rotary shaft is inserted in a bearing bore of a sleeve with lubricant stored therebetween. Upper and lower groove patterns, spaced in a vertical direction for cooperatively generating a dynamic pressure when the rotary shaft rotates in the bearing bore, are formed on at least one of an outside surface of the rotary shaft and an inside surface of the bearing bore. The rotary shaft has a recessed portion in a region located between the upper and lower groove patterns for storing the lubricant therein. The recessed portion is asymmetrically tapered so that the lubricant stored in the recessed portion is chiefly circulated to the upper groove pattern against a gravity acting thereon when the rotary shaft rotates in the bearing bore, whereby the upper and lower groove patterns are uniformly lubricated.

Abstract: A sleeve bore machining apparatus has a plurality of reamers with different diameters, wherein a ball etc. is pressed in and passed through the sleeve bore after a machining with the reamer inserted in the sleeve, measures the push-in load involved in the pass-through operation to select a diameter of the reamer to be used for the next machining process in response to a magnitude of the measured load, or carries out a machining process while a reamer having an edged taper portion or taper stepped portions in a grinding portion is kept inserted in the bore of the sleeve, and controls an extent of insertion of the reamer for the next machining process in response to a magnitude of the measured load, so that the dimensional accuracy of the bore as well as the cylindricity can be successfully machined.

Abstract: A method for manufacturing a fluid bearing of dynamic pressure type by processing an inner peripheral surface of a sleeve bore to form a dynamic pressure-generating groove. An apparatus includes a guide shaft for being coaxially inserted into the sleeve bore while being rotated and fed axially. The shaft has first and second guide holes, and a plurality of balls held in the first and second guide holes. The balls are harder than the sleeve. Also, a diameter of a circumscribed circle about the balls is set to be larger than an inner diameter of the bore of the sleeve.

Abstract: A sleeve bore machining apparatus has a plurality of reamers with different diameters, wherein a ball etc. is pressed in and passed through the sleeve bore after a machining with the reamer inserted in the sleeve, measures the push-in load involved in the pass-through operation to select a diameter of the reamer to be used for the next machining process in response to a magnitude of the measured load, or carries out a machining process while a reamer having an edged taper portion or taper stepped portions in a grinding portion is kept inserted in the bore of the sleeve, and controls an extent of insertion of the reamer for the next machining process in response to a magnitude of the measured load, so that the dimensional accuracy of the bore as well as the cylindricity can be successfully machined.

Abstract: A plurality of processing balls with different outer diameters are prepared at a slidable or rotatable upper stage. One ball, selected from the plurality of prepared balls in correspondence with the inner diameter of a bore of a workpiece, is inserted through the bore while being pressed by a pin.

Abstract: A disk rotating device includes a stationary shaft having one end fixed to a casing, a minor shaft having one end fixed to the casing, a flange member located on one end face of the stationary shaft and being in contact with a contact portion of the minor shaft, a rotary member rotatably mounted around the stationary shaft and supporting a disk, a thrust plate fixed in the vicinity of an end face of the rotary member and being in contact with the flange member, and a motor having a motor stator provided in the casing and a motor rotor provided in the rotary member so as to rotate the disk together with the rotary member around the stationary shaft. A radial bearing groove is provided on at least one of an outer circumferential surface of the stationary shaft and an inner circumferential surface of the sleeve. An outer thrust bearing groove is provided on a surface of at least one of the flange member and the thrust plate, at which the flange member and the thrust plate are in contact with each other.

Abstract: A hydrodynamic gas bearing includes a cantilevered shaft having a free end, a fixed end, and a communicating hole for communicating with a passage formed at an end surface of the free end of the shaft. A cover member is rotatably arranged around the shaft to cover a periphery of the shaft. One of an inner surface of the cover member which faces the fixed end of the shaft and an outer surface of the fixed end of the shaft having a herringbone-configured hydrodynamic pressure generating grooves for preventing gas from being fed from a fixed end side to a free end side of the shaft. One of the inner surface of the cover member which faces the free end of the shaft and an outer surface of the free end of the shaft has helical-configured hydrodynamic pressure generating grooves for feeding gas from the free end side to the fixed end side of the shaft.

Abstract: A processing apparatus with a movable processing tool, includes a deflection detecting device, a rotating position detecting sensor, an arithmetic unit, an output circuit, a fine adjustment device, and an XY table. The detecting device detects a plurality of deflection amounts of a processing reference surface of a to-be-processed work held by a work holding member mounted to a main shaft of an NC processing apparatus. The sensor detects a rotating position of the work. The unit calculates a correcting amount of the tool at a processing point of the work from a measured value of the sensor and plural measured values of the deflection amounts of the detecting device. The circuit outputs the correcting amount synchronously with the rotating position and processing point of the work. The adjustment device has the tool fixed thereto for finely moving the tool in a processing direction based on an output from the circuit. The fine adjustment device is secured to the XY table.

Abstract: A hydrodynamic gas bearing includes a cantilevered shaft having a free end, a fixed end, and a communicating hole for communicating with a passage formed at an end surface of the free end of the shaft. A cover member is rotatably arranged around the shaft to cover a periphery of the shaft. One of an inner surface of the cover member which faces the fixed end of the shaft and an outer surface of the fixed end of the shaft has herringbone-configured hydrodynamic pressure generating grooves for preventing gas from being fed from a fixed end side to a free end side of the shaft. One of the inner surface of the cover member which faces the free end of the shaft and an outer surface of the free end of the shaft has helical-configured hydrodynamic pressure generating grooves for feeding gas from the free end side to the fixed end side of the shaft.

Abstract: A bore processing device for processing an inner surface of a bore of an object to be processed, includes: a taper member having a taper section; a roller arranged to contact and rotate around an outer surface of the taper member; a roller guide member having a guide groove for accommodating the roller and arranged to rotate around the outer surface of the taper member; a first motor for moving the roller guide member to insert the roller into the bore of the object; a second motor for rotating one of the object and the roller guide member; and a third motor for axially moving one of the roller guide member and the taper member so that one of the roller guide member and the taper member relatively moves to the other thereof. The device further includes a detecting device for detecting an axial load applied to the object by the roller when the roller is inserted into the bore of the object.

Abstract: A dynamic pressure type fluid bearing device includes: a shaft; a sleeve into which the shaft is fitted to be rotatable relative to the shaft; two dynamic pressure generating grooves provided on either peripheral surface of the shaft or the inner peripheral surface of the sleeve; and a lubricant held between the shaft and the sleeve. The device has a void, enclosing air, interposed between the two dynamic pressure generating grooves, wherein each of the dynamic pressure generating grooves is not less than four microns in depth and makes an acute angle of less than 20.degree. with a rotational direction of the shaft or the sleeve.

Abstract: A dynamic pressure gas bearing includes a stationary shaft defined by an upper portion, a diameter reduced middle portion having a circumferential grooves running therearound, and a lower portion. A plurality of slanted grooves are formed on the circumferential surface of the upper and lower portions so as to form a herringbone pattern. A rotating unit is mounded on the stationary shaft. When operation, the rotating unit is driven, the air in the gap between the stationary shaft and the rotating unit moves and collects at the circumferential groove. The collected air is guided through a tunnel extending from the side of the circumferential groove to the top end of the shaft 2. The pressurized air blows out toward the end surface of the rotating unit to perform a contactless rotation of the rotating unit.

Abstract: A disk driving apparatus has, a chassis, a fixed shaft having one end attached to the chassis, a hub rotatably mounted around an outer circumferential surface of the fixed shaft and at least one disk mounted on an outer circumferential surface of the hub, the other end of the fixed shaft having a stopper thereon for engaging the hub for retaining the hub on the fixed shaft, a disk fixing plate positioned over the other end of the fixed shaft and fixing the one disk to the hub and having a surface opposed to the other end of the fixed shaft, a thrust bearing element movably mounted between the disk fixing plate surface and one of the other end of the fixed shaft and the stopper, and a hydrodynamic pressure generating groove formed in one of a herringbone pattern and a helical pattern and being on one of an outer circumferential surface of the fixed shaft and an inner circumferential surface of the hub.

Abstract: Modular coil cores for an electric motor eliminate tedious coil winding on pole members by making either the pole caps or the complete pole members of the stator yoke engageable with and disengageable from the stator yoke itself.

Abstract: A self acting gas bearing apparatus comprising a cantilevered shaft, a sleeve that is fitted to the shaft so as to be freely rotatable around the shaft, and a lid that is fixed onto one end of the sleeve, wherein one or more intake holes having filters thereon are provided on the sleeve or lid in the vicinity of the free end side of the shaft, and dynamic pressure generating grooves that force gas from the intake holes toward the fixed end side of the shaft are provided on the outer surface of the shaft or the inner surface of the sleeve, whereby fine particles are prevented from entering into a bearing clearance between the shaft and the sleeve, thereby ensuring a smooth rotation of the sleeve around the shaft without coming into contact with the shaft.

Abstract: A hydrodynamic bearing device which includes a shaft, a ring-shaped member and a thrust bearing member, with a lubricating material being held in a space defined in the thrust bearing member and the inner peripheral face of the ring-shaped member. The ring-shaped member is formed, in its inner peripheral face, with a taper for feeding the lubricating material into the thrust bearing member based on centrifugal force, by which the lubricating material is prevented from flowing out.

Abstract: A rotary head cylinder device with a fluid bearing having a lower cylinder, a fixed shaft supported at its bottom in a cantilever way, a sleeve rotatably fitted on the shaft and cylindrical rotary transformers arranged coaxially with the shaft, the shaft having herringbone groove patterns formed thereon with a larger surface area of the herringbone groove pattern on the free end side of the shaft than on the fixed end side thereof, thereby providing a compact structure.