Abstract: A disc driving motor of the invention includes a base, a hub having a ring-shaped disc receiving face on which a disc is placed, a hydrodynamic bearing rotatably supporting the hub, a motor unit mounted on the base, the motor unit having an outer diameter larger than that of the disc receiving face and applying a rotational force to the hub, and a magnetic shield plate disposed on an axial clearance formed between the disc and the motor unit when the disc is placed on the disc receiving face. The magnetic shield plate has an opposed face opposed to the disc when the disc is placed on the receiving face, the opposed face being inclined toward the disc receiving face.

Abstract: There are provided a thrust plate with which there is less warpage when the thrust plate has been incorporated into a hydrodynamic bearing device, which improves the reliability of the hydrodynamic bearing device, as well as a hydrodynamic bearing device, a spindle motor, and an information apparatus equipped with this thrust plate, and a method for manufacturing a thrust plate. With a thrust plate that is provided at one end of a shaft of a hydrodynamic bearing device and that closes off one end of a sleeve formed so as to surround the shaft via a lubricating fluid (oil), a laser irradiated portion is provided to the opposite side of the thrust plate from the side facing the shaft in order to reduce the warpage that is produced by the formation of a hydrodynamic groove on the side facing the shaft, and the warpage that occurs during assembly, etc.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: The invention provides a motor which is mainly used in an HDD, maintains high accuracy without runout even upon rotation at high speed, and is excellent in resistance to external forces. A disc driving motor of the invention includes: a base; a hub having a ring-shaped disc receiving face on which a disc is placed; a hydrodynamic bearing rotatably supporting the hub; a motor unit mounted on the base, the motor unit having an outer diameter larger than that of the disc receiving face and giving a rotational force to the hub; and a magnetic shield plate provided on an axial clearance formed between the disc and the motor unit when the disc is placed on the disc receiving face. Herein, the magnetic shield plate is fixed while being inclined to the disc receiving face such that a pressure of an airflow in the axial clearance differs for each circumferential position upon rotation of the disc.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

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.