摘要:
A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around the support shaft, thrust and radial bearings disposed between the stator and the rotor, a stator coil secured to the stator, and a rotor magnet member secured to the rotor opposing the stator coil. The thrust and radial bearings are hydrodynamic bearings. A movable piece that constitutes a part of the thrust bearing is secured to the lower end of a cylindrical portion of the rotor and extended outwardly or inwardly from the cylindrical portion, or is disposed above the rotor. The stator coil is secured to the outer peripheral portion of the support shaft above or below the radial bearing. The rotor magnet member is securd to the inner peripheral surface or inner top surface of the rotor. Either a radial or axial gap is provided between the stator coil and the rotor magnet member.
摘要:
A bearing structure suitable for a spindle motor or the like, which enables such a motor to rotate with minimal vibrations. The bearing structure comprises a stator including a support shaft which is disposed on a base, and a rotor which is rotatably disposed around the support shaft. A radial hydrodynamic bearing and a thrust hydrodynamic bearing are disposed between the stator and the rotor. The stator has the support shaft, a thrust plate and a radial cylindrical member which is concentric with the support shaft. The thrust plate is secured to an end surface of the radial cylindrical member. The support shaft extends through the centers of the radial cylindrical member and the thrust plate. The rotor has a radial sleeve. The radial hydrodynamic bearing is formed from the inner peripheral surface of the radial sleeve and the outer peripheral surface of the radial cylindrical member, which face each other and either of which is formed with herringbone-shaped grooves for generating dynamic pressure. The thrust hydrodynamic bearing is formed from an end surface of the radial sleeve and a sliding surface of the thrust plate, which face each other and either of which is formed with spiral grooves for generating dynamic pressure. A rolling bearing may be added in order to minimize the starting torque in the bearing structure.
摘要:
A hydrodynamic bearing for a spindle motor used in an environment of high degree of cleanness. A sliding surface of the hydrodynamic bearing is formed of a ceramic material with a surface roughness Ra not larger than 0.3 microns, and this sliding surface is coated thinly with at least one lubricant selected from among perfluoropolyethers having a functional group reactive with the ceramic material, thereby providing on the sliding surface a uniform thin film with a thickness in the range of from 20 to 100 angstrom and having protecting and lubricating functions. The lubricant is selected from among hydroxyl group-containing perfluoropolyethers, carboxyl group-containing perfluoropolyethers, and ester group-containing. The lubricant contains an antistatic agent.
摘要:
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, which is surrounded by these chamfer portions and one thrust plate (3), a lubricating liquid is employed as a fluid for generating dynamic pressure in the radial hydrodynamic bearing, small holes (8) for collecting the lubricating liquid are formed in the outer peripheral surface of the radial cylindrical member (4), and lubricating liquid is sealed in the bearing clearance of the radial hydrodynamic bearing by virtue of the presence of the air gaps (13).
摘要:
A ceramic hydrodynamic bearing used as a radial or a thrust bearing in a spindle motor for a hard disk driver. The bearing includes a ceramic bearing base having hydrodynamic pressure generating grooves. A sliding surface of the bearing base is irradiated with an energy beam with a high energy density to remove said material, thereby forming hydrodynamic pressure generating groove, and at the same time the grooves are coated with a modification layer that is formed by melting the ceramic material that constitutes said ceramic bearing base with the energy beam and by solidifying said ceramic bearing base.
摘要:
It is an object of the present invention to provide a device suitable for new usage by making use of a semiconductor device such as an RFID tag in terms of the capability to transmit and receive data without being contacted therewith, to decrease a burden on a user, and to improve convenience. A semiconductor device is provided to have an arithmetic processing circuit including a transistor, a conductive layer serving as an antenna, a detecting unit having a means for detecting physical quantity or chemical quantity, and a storage unit for storing data detected by the detecting unit, and to cover the arithmetic processing circuit, the conductive layer, the detecting unit, and the storage unit with a protective layer. In addition, diverse information can be monitored and controlled by providing such a semiconductor device for human beings, animals and plants, or the like without being contacted therewith.
摘要:
A semiconductor device with improved convenience is provided by having an antenna for converting an electromagnetic wave into an electric signal, a detecting portion for detecting chemical reaction, and a control portion for controlling the antenna and the detecting portion. The detecting portion includes at least a detecting element, and the control portion includes at least a transistor. The detecting element includes a reactive layer for solidifying at least any one of a nucleic acid, a protein, an enzyme, an antigen, an antibody and a microbe. Alternatively, a semiconductor device includes an antenna, a detecting portion, a control portion, and a memory portion. The memory portion includes at least a memory element, and the memory element includes a first conductive layer, a second conductive layer, and a layer between the first conductive layer and the second conductive layer.
摘要:
It is an object of the present invention to provide a device suitable for new usage by making use of a semiconductor device such as an RFID tag in terms of the capability to transmit and receive data without being contacted therewith, to decrease a burden on a user, and to improve convenience. A semiconductor device is provided to have an arithmetic processing circuit including a transistor, a conductive layer serving as an antenna, a detecting unit having a means for detecting physical quantity or chemical quantity, and a storage unit for storing data detected by the detecting unit, and to cover the arithmetic processing circuit, the conductive layer, the detecting unit, and the storage unit with a protective layer. In addition, diverse information can be monitored and controlled by providing such a semiconductor device for human beings, animals and plants, or the like without being contacted therewith.
摘要:
A glycoside represented by formula (I), wherein dexamethasone or betamethasone is the aglycon and the 21-position is substituted by a simple sugar or an acylated sugar selected from the group consisting of glucose, galactose, mannose, rhamnose, fucose, N-acetylglucosamine, N-acetylgalactosamine, galacturonic acid, glucuronic acid and sialic acid. ##STR1##