Abstract: A motor which includes a core having two or more coiled teeth; a base to which the core is secured; and a terminal assembly secured to the base. The terminal assembly has lands for attaching coil ends, and is secured to the base by welding. This terminal assembly is configured by assembling at least next three components: an upper terminal holder which is an insulator; a terminal which is a conductor; and a lower terminal holder which is an insulator.

Abstract: In a brushless motor, a projected annular portion is formed in a central portion of a rotor frame and the projected annular portion has a bore that includes a small-bore portion and a large-bore portion. A length L1 of the small-bore portion is in a range of D×0.05≦L1≦D×0.20, where D represents the diameter of the shaft. An axial length L2 of the projected annular portion is arranged to satisfy L2≧L1×2. Thus, the brushless motor realizes a small and thin construction and has a high deflection precision as well as high productivity.

Abstract: A motor has plural through-holes punched in a top surface of its frame. A cap made of magnetic material is placed at a location on a stator which corresponds to the through-holes, and the cap is spaced axially from the through holes. An attracting magnet is placed outside the cap. This structure allows a bearing to hold its oil, and generates attracting force in an axial direction without adversely affecting driving-magnetic-circuits. As a result, an apparatus using this motor can be low in profile and run at a high speed.

Abstract: A motor which includes a core having two or more coiled teeth; a base to which the core is secured; and a terminal assembly secured to the base. The terminal assembly has lands for attaching coil ends, and is secured to the base by welding. This terminal assembly is configured by assembling at least next three components: an upper terminal holder which is an insulator; a terminal which is a conductor; and a lower terminal holder which is an insulator.

Abstract: Fluid bearing equipment which is free from lockup or seizure which may occur due to a deficiency of a lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment. The fluid bearing equipment is arranged such that maximum pressure generating portions 23 of dynamic pressure generating grooves 15, 16 provided in a thrust-side dynamic pressure generating portion are located closer to the outer circumference of a stationary thrust plate 9 than a radially middle position of the thrust-side dynamic pressure generating portion. With this arrangement, the lockup and seizure of a motor can be prevented which may otherwise occur due to a deficiency of the lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment.

Abstract: A motor has plural through-holes punched on a top surface of its frame, and a cap made of magnetic material is placed at a place on a stator, where the place corresponding to the through-holes and spaced axially from the through-holes. An attracting magnet is placed outside the cap. This structure allows a bearing to hold its oil, and realizes to generate attracting force in an axial direction without adversely affecting driving-magnetic-circuits. As a result, an apparatus using this motor can be low-profile and run at a higher speed.

Abstract: In a brushless motor, a projected annular portion is formed in a central portion of a rotor frame and the projected annular portion has a bore that includes a small-bore portion and a large-bore portion. A length L1 of the small-bore portion is in a range of D×0.05≦L1≦D×0.20, where D represents the diameter of the shaft. An axial length L2 of the projected annular portion is arranged to satisfy L2≧L1×2. Thus, the brushless motor realizes a small and thin construction and has a high deflection precision as well as high productivity.

Abstract: A hydrodynamic bearing which prevents a lubricating fluid from scattering out of the dynamic pressure generating portion. The bearing includes radial spacing d of a gap at an open end of the thrust-side dynamic pressure generating portion, whose value is greater than a spacing of the thrust-side dynamic pressure generating portion, as measured relative to the thrust direction. Scattering of lubricating fluid from the open end of the thrust-side dynamic pressure generating portion is therefore prevented even when the bearing rotates at a high speed in a high temperature envivronent.

Abstract: An object of the present invention is to provide a hydrodynamic bearing device which has an improved construction to prevent a lubricating fluid from scattering out of a dynamic pressure generating portion. The hydrodynamic bearing device of the present invention is characterized in that a radial spacing &Dgr;d of a gap at an open end of a thrust-side dynamic pressure generating portion is set greater than a spacing 26 of the thrust-side dynamic pressure generating portion as measured with respect to the thrust direction. With this arrangement, the scattering of the lubricating fluid from the open end of the thrust-side dynamic pressure generating portion is prevented even when the hydrodynamic bearing device is operated at a high rotation speed in a high temperature environment.

Abstract: An object of the present invention is to provide a fluid bearing equipment which is free from lockup or seizure which may occur due to a deficiency of a lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment. The fluid bearing equipment is arranged such that maximum pressure generating portions 23 of dynamic pressure generating grooves 15, 16 provided in a thrust-side dynamic pressure generating portion are located closer to the outer circumference of a stationary thrust plate 9 than a radially middle position of the thrust-side dynamic pressure generating portion. With this arrangement, the lockup and seizure of a motor can be prevented which may otherwise occur due to a deficiency of the lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment.

Abstract: A brushless motor includes (a) a rotor magnet having plural magnetic polarities and (b) a stator core facing the rotor magnet via an annular space. The stator core has plural teeth wound by coils, and a teeth width ranges from not less than 1.7 mm to not more than 2.2 mm, or an outer diameter of the rotor core vs. the teeth width ranges from not less than 8 to not more than 12. This structure allows the brushless motor to rotate with less vibrations, lower noise and lower current consumption.

Abstract: It is an object of the present invention to provide a motor capable of reducing a loss as much as possible, and securing minimum vibration proof performance and reliability by definitely defining the upper and lower limits of a minimum shaft diameter in conformity with a disk load, the service number of revolutions or the like. In a shaft-fixed type motor of the fluid bearing specifications, the diameter d (mm) of a fixed shaft is set so as to satisfy the relation of &agr;3·M1 >d3>M1, where M1=J1·(N/1000)2·k2·D, J1 being a coefficient to be experimentally determined, N(rpm) the service number of revolutions, k the number of a disk-shaped recording media, D (inch) the diameter of the disk-shaped recording medium, and &agr; a ratio of the maximum diameter to the minimum diameter of the fixed shaft.

Abstract: Herringbone grooves are formed on an inner wall of a sleeve through which a motor shaft is inserted. Lubricating fluid is provided between a space between the shaft and the sleeve so as to form a relatively rotatable radial dynamic pressure bearing. A surface layer and the herringbone grooves on an inner wall of the sleeve, which are sliding regions with the motor shaft, have a different hardness from that of a base material of the sleeve. The hardness ratio of these two elements is set so that the shaft spins without wearing itself out as well as the sleeve surface layer. As a result, a highly reliable motor is achieved because the structure can maintain accurate whirling and suppress seizure due to abrasion powder between the shaft and the sleeve.

Abstract: In a spindle motor for a driving a memory disk, a is closed space formed by a sleeve metal, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Abstract: In a spindle motor for a driving a memory disk, a closed space is formed by a sleeve, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Abstract: A memory disk driving apparatus has a dynamic pressure fluid bearing type spindle motor 1, wherein herringbone grooves 12a are formed on the shaft 12. In the dynamic pressure fluid bearing relatively rotatable with the intermediary of the lubricant injected into a gap between the shaft 12 and the sleeve 13; the shaft diameter D is selected 4 mm or less, and the ratio of the radial gap R between the shaft and the sleeve to the diameter D of the shaft (R/D) is between 0.0005 and 0.002.

Abstract: A disk driving apparatus solves such problems that the position of a rotor is unstable and likely to float, and the rotor is displaced when an excessive acceleration is applied thereto, so that a hydrodynamic bearing mechanism can be used. This apparatus uses a single surface opposing type mechanism in a thrust bearing of a motor. It has a device using a magnetic attraction force to stabilize the position of the rotor and various devices for limiting the amount of movement of the rotor, in which devices members which physically contact the rotor and lock in are provided. As a result, a thrust bearing mechanism can be formed by use of a single surface opposing type thrust bearing which is simple in construction. Advantages such as low height, simplicity in construction, low price, or low consumption of power can be obtained. In particular, the feature of low height is extremely advantageous when a hydrodynamic bearing is used in a thin type apparatus.

Abstract: A cylindrical shielding plate is provided on an inner circumference of the cylindrical recess formed on the bracket of an electric motor of a magnetic disk drive, and an open sector of the stator core is arranged to coincide with the moving direction of read/write head. Or a cylindrical boss is inserted between the stationary shaft and the stator core. Thereby, high frequency electromagnetic noise to the magnetic disk is drastically reduced.

Abstract: A cylindrical shielding plate is provided on an inner circumference of the cylindrical recess formed on the bracket of an electric motor of a magnetic disk drive, and an open sector of the stator core is arranged to coincide with the moving direction of read/write head. Or a cylindrical boss is inserted between the stationary shaft and the stator core. Thereby, high frequency electromagnetic noise to the magnetic disk is drastically reduced.