Abstract: It is an object of the invention to provide a hydrodynamic bearing which can be easily worked and assembled and in which a liquid is prevented from leaking.

Abstract: In a dynamic pressure bearing apparatus having a fixed shaft, dynamic pressure generating grooves formed at least on one side of circularly facing surfaces of a rotor and of the fixed shaft which is rotatably meshed with the rotor, a radial bearing formed in an axial direction and a thrust bearing is formed by one end of the fixed shaft and axially facing surfaces of the rotor, the rotor is rotatably supported against the fixed shaft by air dynamic pressure which is generated in the radial bearing and the thrust bearing. The radial dynamic pressure bearing generating grooves are formed on the radial bearing in a dynamic pressure groove shape which pumps air pressure toward the thrust bearing side. An air guide hole is formed in the fixed shaft from the one end to another end of the fixed shaft.

Abstract: A bearing device where a sliding bearing rotatably supporting a shaft is molded with an inexpensive sintered material, three asymmetrical circular arc-shaped radial bearings are formed in the inner peripheral surface of the shaft, taper land-shaped thrust bearings are formed in the opposite end surfaces of the radial bearing surface, T-shaped bubble removing means which is constituted by axial and radial flow passages formed in the shaft opposed to the radial bearing is provided, and magnetic fluid is used as a lubricant. A magnetic disk unit using the bearing device is also disclosed.

Abstract: A hydrodynamic bearing according to this invention and an electric motor with this hydrodynamic bearing include a shaft having a lubricating-fluid filling hole, one end of which is open toward the outside of the motor and the other end of which leads to the gap between the shaft and a sleeve in which lubricating fluid is filled. At least part of the filling hole except for the opening facing the outside of the motor has a smaller diameter than that of the outer opening. An elastic member formed of elastic material is inserted into the lubricating fluid fillng hole.

Abstract: A bearing system for brushless DC motors is disclosed. The bearing system has an electromagnetic force generator in a bearing so as to generate an electromagnetic force or a magnetic force. The bearing system thus magnetically attracts the shaft when eccentricity of the shaft in the bearing is reduced during a high speed operation of the shaft, thus allowing the shaft to keep desired eccentricity in the bearing and increasing dynamic pressure of oil in the bearing and preventing a formation of an oil whirl, and improving dynamic characteristics of the motor such as low operational vibrations and noises during a high speed operation of the motor.

Abstract: A journal bearing apparatus capable of varying the clearance between a bush which protrudes from the inner surface of a sleeve in which a rotation shaft is inserted and the outer surface of the rotation shaft, in the longitudinal direction of a first dynamic pressure generating groove. Moreover, a journal bearing apparatus is capable of varying the clearance between one end of the rotation shaft and the surface of a thrust bearing, in the diametral direction of a second dynamic pressure generating groove. The clearance becomes wider towards the central part from the ends of the bush, or towards the central part from the edge parts of the surface of the thrust bearing. The shape of the end of the bush or the thrust bearing is preferably a circular arc. Thereby, the fluid pressure on the rotation shaft which faces the first and second dynamic pressure generating grooves is uniform.

Abstract: A miniature motor having a rotor arranged within a casing within which a stator is mounted, and a rotary shaft of the rotor is supported by bearing units mounted on both ends of the casing. One of the bearing units is provided with a thrust receiving member for supporting an end portion of the rotary shaft in a thrust direction, and a bearing for supporting the rotary shaft in a radial direction within a rotary shaft insertion hole. The thrust receiving member having a dimension that is equal to or smaller than an inner diameter of a bottomed recess formed in the casing is laid on a flat bottom surface of the bottomed recess. The bearing is securely fixed within the bottomed recess and contacted against the thrust receiving member. The rotary shaft insertion hole is in fluid communication with a through-hole formed in a bottom plate of the bottomed recess.

Abstract: A hydrodynamic bearing device includes a gap between a shaft and shaft holder. One of the shaft and shaft holder has a recess for separating by capillary action lubricant at an upper portion of the gap above the recess from lubricant at a lower portion of the gap below the recess. The separated lubricant at the recess forms a gas interposition in order to reduce lubricant resistance. A hole formed in the shaft or shaft holder communicates the air interposition to the external atmosphere to prevent air expansion and the build-up of bubbles in the lubricant which could otherwise cause contamination and leakage. An axially extending storage groove supplies by capillary action lubricant from either the upper or lower portion to the other portion if lubricant in the other portion decreases due to vaporization or leakage, whereby the loss of lubricant is minimized and the operating life of the surrounding components are increased.

Abstract: The present invention includes four sections or partitions: two thrust bearings which are formed by the sides of a grooved thrust plate and corresponding countersurfaces, the thrust bearings designed to cause fluid flow in a single direction up around the rotating thrust plate and upward along the surface of a rotating journal, and two journal bearings formed side-by-side on the journal formed between a rotating shaft and a bushing with multiple spiral-grooved sections being formed on the rotating shaft or in the stationary bushing. The two journal bearings are separated by a circumferential groove in the shaft which is connected by a radial bore to a hollow reservoir in the shaft for providing fluid to the journal bearing and the thrust bearing. By providing this bore and a second bore located near to the thrust bearing, the boundary conditions for the combined journal bearings and thrust bearings are fixed and a stable rotating shaft is achieved.

Abstract: A hydrodynamic bearing journaling a shaft includes a rotatable bushing journaling the shaft and thrust plates on the shaft at opposite ends of the bushing. The bushing is encased in a cylindrical sleeve. Lubricant containing clearance spaces are formed between the shaft, bushing, sleeve, and thrust plates. An internal radial chamber in the sleeve between the bushing and sleeve stores lubricant and collects foreign particles. Radial ports through the bushing provide for flow of lubricant between the journal bearing and the shaft and thrust plates.

Abstract: A base board supported on an X-Y stage or the like of an exposure apparatus includes a cylindrical fixed member. Porous pads held on the fixed member support the inner circumferential surface of a guide member provided as one body with a holding member for holding a wafer in a non-contact state. The base board is rotated around its central axis by a .theta. linear motor, and is reciprocated in the vertical direction by Z linear motors provided at an equal interval in the circumferential direction. Each of the Z linear motors and the .theta. linear motor includes a rotor fixed to the holding board, and a stator that includes a coil fixed to the base board.

Abstract: The present invention includes four sections or partitions: two thrust bearings which are formed by the sides of a grooved thrust plate and corresponding countersurfaces, the thrust bearings designed to cause fluid flow in a single direction up around the rotating thrust plate and upward along the surface of a rotating journal, and two journal bearings formed side-by-side on the journal formed between a rotating shaft and a bushing with multiple spiral-grooved sections being formed on the rotating shaft or in the stationary bushing. The two journal bearings are separated by a circumferential groove in the shaft which is connected by a radial bore to a hollow reservoir in the shaft for providing fluid to the journal bearing and the thrust bearing. By providing this bore and a second bore located near to the thrust bearing, the boundary conditions for the combined journal bearings and thrust bearings are fixed and a stable rotating shaft is achieved.

Abstract: A construction for a fluid bearing in a rotary spindle apparatus includes a spindle having first and second ends, and at least one thrust plate coupled to a shaft which is surrounded by a hub having an enclosing sleeve. The sleeve surrounding the thrust plate and shaft defines several gap regions where bearing fluid resides. A first radial gap region is defined between the shaft and sleeve and a second radial gap region is defined between the outer diameter of the thrust plate and the sleeve. A first axial gap region is defined by an upper surface of the thrust plate and the sleeve, and a second axial gap region exists between the lower surface of the thrust plate and the sleeve. A bearing fluid is disposed within these gap regions and forms capillary seals at first and second ends of the spindle. The thrust plate includes holes or pressure compensation ports which connect the first and second axial gap regions.

Abstract: An electric motor construction includes a rotor housing and sleeve which surrounds a shaft/thrust plate. The thrust plate is enclosed in a dead end cavity and is surrounded by a fluid which forms a fluid bearing. The shaft has asymmetrical grooves which create a net pressure gradient from a capillary seal formed near the bottom of the shaft toward the dead end cavity. This helps maintain the capillary seal and reduce the risk of cavitation.

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 bearing device suitable for a spindle motor, which comprises a base, a spindle stood on a central portion of the base, a radial cylindrical member (4) fixed on the spindle, a pair of thrust plates (3) secured to both end surfaces of the radial cylindrical member, and a radial sleeve (6) rotatably supported by the thrust plates (3) and the radial sleeve (6), wherein a radial hydrodynamic bearing is formed by the radial cylindrical member (4) and the radial sleeve (6), thrust hydrodynamic bearings are formed by both end portions of the radial sleeve (6) and the thrust plates (3), a gas is employed as a fluid for generating dynamic pressure in the thrust hydrodynamic bearings, the radial bearing has a minute clearance, a chamfer portion is provided on the outer periphery of each end of the radial cylindrical member (4), and another chamfer portion is provided on the inner periphery of each end of the radial sleeve (6), thereby providing an air gap (13) at each axial end of the radial hydrodynamic bearing, whic

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 rotating device possesses a fixed portion and a movable portion equipped with a rotary shaft, and is equipped with a rotor that can be fastened in an integrated manner to the rotary shaft via a fastening device. Said rotating device is composed of a driving device which directly rotates the rotary shaft, a fluid bearing device which reduces the friction between the fixed portion and the movable portion, a disk provided on the movable portion which is elastically deformable in the direction of thrust, a clamping device provided on the fixed portion which stops the rotation of a turntable by clamping the disk, a positioning jig which makes fine changes in the position of the rotor in the radial direction with respect to the rotary shaft, and a monitoring device which monitors the status of rotation of the rotor.

Abstract: A floating, self-centering impeller for a turbine pump assembly has a plurality of "D-shaped" recesses arranged in one or more circumferential rows on its end surfaces to induce pressurized film between its end surfaces and adjacent thrust surfaces of side plates to prevent galling or seizing of the pump as the impeller is rotated. A corresponding array of such "D-shaped" recesses may be provided on the opposing surfaces of the side plates.

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 hydrodynamic bearing system comprises a shaft, a sleeve rotatably fitted on the shaft and a thrust plate fixed to the sleeve and acting to support one end of the shaft in a thrust direction. First shallow grooves are formed in at least one of fitted surfaces of the shaft and of the sleeve to support one of the shaft and the sleeve with respect to the other in a radial direction, and a second shallow groove is formed in at least one of the shaft and the thrust plate with respect to the other in a thrust direction. The thrust plate is made of material including resin material as a main component and has an outside periphery portion with a thickness thicker than that of an inside periphery portion thereof.

Abstract: A rotary machine for handling a fluid includes a housing having a rotor chamber and a rotor rotatably mounted in the chamber. The rotor has a plurality of generally radially disposed vane slots, and a plurality of vanes are slidably mounted in the vane slots and operable to define variable volume chambers for the fluid as the rotor rotates and the vanes move generally radially in and out of the vane slots. The vanes have projections projecting from the longitudinal ends thereof, and the housing has annular rings having inner cylindrical surfaces disposed to be engaged by projections. Grooves on the outer surface of the rings are operable to produce a layer of fluid between such outer surface and the housing to thereby minimize the frictional rotational resistance of the rings on the housing, the rings thereby being rotated in approximately synchronization with the rotor.

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 dynamic pressure bearing device a relatively rotatable shaft member and sleeve member, accommodating the shaft member, are relatively supported with respect to a thrust direction and a radial direction, and wherein there is provided a circulation passageway for circulating a fluid along at least a part of a thrust surface between the shaft member and the sleeve member.

Abstract: A rotary machine for handling a fluid includes a housing having a rotor chamber and a rotor rotatably mounted in the rotor chamber. The rotor has a plurality of generally radially disposed vane slots and a plurality of vanes are slidably mounted in the vane slots and operable to define variable volume chambers as the rotor rotates and the vanes move generally radially in and out of the vane slots. Rotatable retainer plates are disposed between the housing and the longitudinal ends of the vanes, the retainer plates having stoppers extending axially into recesses in the vanes, the stoppers being operable to limit the extent of outward radial movement of the vanes to preclude sliding contact between the vanes and the inner peripheral surface of the rotor chamber.

Abstract: A vane pump in which a projection is provided on the end of a vane which radially slides as a rotor rotates, and an annular race concentric with an inner peripheral surface of a housing is provided in the inner surface of the end wall of the housing, the projection being brought into engagement with the annular race to control the slide of the vane.

Abstract: A housing has a vertically extending cylindrical bore, with a radical bearing surface formed on the inner peripheral surface, and a thrust bearing surface formed on the inner bottom surface of the cylindrical bore. A shaft member which is supported rotatably in the cylindrical bore of the housing has a radial receiving surface and a thrust receiving surface respectively formed on the outer peripheral surface and the bottom surface. A dynamic pressure generating groove of a spiral shape is formed in at least one of the radial bearing surface and ther radial receiving surface. When the shaft member is rotated, a gas in the housing is sucked by the pumping action of the dynamic pressure generating groove and flows into a pressure chamber between the thrust bearing surface and the thrust receiving surface through a radial space between the radial bearing surface and the radial receiving surface. The pressure in the pressure chamber maintains the shaft member in a floating position by a predetermined amount.

Abstract: The spindle has a sleeve about a fixed shaft. Swing-type bearing pads are attached to the fixed shaft. The bearing pads are lubricated by flowing a lubricant through primary and secondary lubricating holes located in the fixed shaft.

Abstract: A gas-static and gas-dynamic radial bearing assembly includes a shaft having a supply line extending in the interior thereof for bearing gas. The shaft has a portion in the form of a porous sintered body. A bearing has a given bearing length, part of which is occupied by the porous sintered body. The bearing has a bearing box divided into individual segments partly overlapping one another at given regions. Spring elements in the vicinity of said given regions spread said segments apart.

Abstract: Disclosed is a dynamic pressure gas bearing device in a rotational unit in which a rotational member put on a cantilevered fixed shaft is designed such that an operating gas generated by a dynamic pressure groove formed between the fixed shaft and the rotational member is directed into a pressure chamber between the fixed shaft and the rotational member and supports the rotational member in the thrust direction and that the pressure in the pressure chamber is adjusted by a hole formed in the fixed shaft or the rotational member.

Abstract: A dynamic pressure type fluid bearing device in which a housing and a shaft rotatable relative to each other are opposed to each other to provide inner and outer bearing surfaces for radial load. One of these bearing surfaces is formed with a groove for generating dynamic pressure and the housing and the shaft are opposed to each other in a first and a second bearing surface for thrust load. A circulation path for circulating lubricant is formed in at least one of the housing and the shaft and opens in the first and/or second bearing surface.

Abstract: In a superprecision lathe of the present invention, a main spindle having mounted at one end thereof a vacuum chuck rotatably supported in an air bearing fixed on a headstock. There is formed within the main spindle a first vacuum passage connected to the vacuum chuck and opened at the outer surface of the main spindle, and a second vacuum passage formed in the headstock and of which an open end to be connected to a vacuum pump and is opened at the inner surface of the air bearing. The first vacuum passage is connected to the second vacuum passage through an interconnection region defined by two annular grooves formed at the opposite positions of the outer surface of the main spindle and the inner surface of the air bearing; therefore, it is not necessary to use a specific sealing member, any external vibration is not transmitted to the main spindle, and the object can be worked effectively with a high speed rotation of the main spindle.

Abstract: A dressing roll unit is supported on a nonrotating shaft clamped and maintained as a "fixed end" beam, thereby restrained against axial movement and deflection. The shaft is formed with spaced-apart bearing points, wherein wedge-shaped relief sectors are formed about the shaft at the bearing points, and a roll body is maintained about the bearing points with an annular clearance. Rotation of the dressing roll body and roll thereby forms high pressure hydrodynamic wedges of oil at the relief sectors and annular clearances, to create an extremely rigid roll mounting unit, without the need for pivoting bearing parts.

Abstract: An aerostatic or aerodynamic bearing comprising a stationary part and a movable part with cooperating bearing surfaces between which there is formed a bearing gap which at one area communicates with an air inlet and at another area opens into the atmosphere. The air inlet comprises one or more filters, and at least one of the bearing surfaces is provided with a pressure-equalizing groove near the area at which the bearing gap opens into the atmosphere.

Abstract: A procedure is described for the balancing of rotors without journals, as well as an auxiliary bearing arrangement used to accomplish the balancing of such rotors. Fluids function to separate the rotor being balanced from the journal exterior of the bearing arrangement and also to separate the rotor from the support surface of the bearing arrangement. A high level of precision is achieved while avoiding fixed or expanding mandrels. Improvement of the automated operation of balancing machines of this type is possible without wear on the machine. Also, additional disturbance frequencies are avoided.

Abstract: The bore of a bearing bush for a gear pump has a first recess located in a zone of load concentration in the bore, the first recess being supplied with a fluid under pressure. A second recess in the bore is located wholly outside the zone in which concentrated loads occur and acts as a reservoir for fluid, to prevent cavitation within the bore as a result of low pressures caused by radical movements of a shaft within the bush. A passage connects the second recess with a zone of lower pressure within the pump.

Abstract: A dynamic pressure type fluid bearing device including a housing having a bearing hole, a shaft rotatably provided in this bearing hole, and a thrust bearing member attached to an end of the housing, wherein a groove is provided in either the shaft or the bearing hole, another groove is provided in the contacting surface between the thrust bearing member and the shaft, a ventilation flute to communicate with the atmosphere is provided in the contacting surface between the thrust bearing member and the housing, and a lubricant is charged around the groove, so that the lubricant is prevented from flowing out due to changes in the atmospheric pressure or environment.

Abstract: A dynamic pressure type fluid bearing comprises a housing provided with a cylindrical hole having a cylindrically shaped inner bearing surface for radial load and a bottom bearing surface for thrust load, and a shaft disposed in the cylindrical hole and having a cylindrically shaped outer bearing surface for radial load opposed to and cooperative with the inner bearing surface and an end bearing surface for thrust load opposed to and cooperative with the bottom bearing surface. At least one of the inner bearing surface and the outer bearing surface is provided with grooves for generating a dynamic pressure. A communication hole is provided in the bottom bearing surface and opens to the outside of the housing. The bottom bearing surface has around the communication hole an annular contact bearing surface which contacts the end bearing surface when the bearing is stationary.

Abstract: A motor comprises a housing, a cylindrical stationary shaft placed upright on the housing, and a rotational shaft rotatably and coaxially supported by the stationary shaft. The rotational shaft has a cylindrical hollow portion coaxially formed therewith, open at one end of the rotational shaft, and into which the stationary shaft is inserted. The motor further comprises a first dynamic pressure type bearing formed on the outer peripheral surface of the stationary shaft for generating a dynamic pneumatic flow between the outer peripheral surface of the stationary shaft and the peripheral surface of the hollow portion to bear the radial load of the rotational shaft, and a second dynamic pressure type bearing formed on the outer peripheral surface of the stationary shaft for generating a dynamic pneumatic flow between the outer peripheral surface of the stationary shaft and the peripheral surface of the hollow portion to bear the thrust load of the rotational shaft.

Abstract: In a motor unit, a motor shaft is supported by a pair of journal bearings of a herringbone dynamic pressure type. A polygonal mirror is fixed to one end of the motor shaft, and a magnetic thrust bearing is arranged at the other end so that the motor shaft is suspended thereby. The magnetic thrust bearing is formed of ring-shaped first and second permanent magnets. The first permanent magnets are coaxially fixed to the motor shaft and each have one pole on their outer surfaces. The second permanent magnets are fixed to a motor housing, and have their inner surfaces opposed to the outer surfaces of the first permanent magnets. The inner surface of each second permanent magnet has a pole different from that of its corresponding first permanent magnet. The first and second permanent magnets attract one another so that the motor shaft is suspended by attraction.

Abstract: This disclosure is concerned with improvements in hydrostatic guide bearings of a shaft in which the journal of the shaft takes on the form of a sleeve and the bearing comprises a first and a second set of chambers placed within concentric races respectively opposite the internal and external walls of the journal.