Abstract: A direct-current (DC) brushless motor is provided for realizing an easy winding operation, a flat shape, effective utilization of a magnetic force, improved magnetic characteristics of a stator core, and a good rotation driving efficiency particularly at a higher rotational speed region. The DC brushless motor switches conduction to windings wound around a stator core fixedly disposed corresponding to a rotatable rotor on which a permanent magnet is fixed, to generate a rotating magnetic field which causes the rotor to rotate.

Abstract: A direct-current (DC) brushless motor is provided for realizing an easy winding operation, a flat shape, effective utilization of a magnetic force, improved magnetic characteristics of a stator core, and a good rotation driving efficiency particularly at a higher rotational speed region. The DC brushless motor switches conduction to windings wound around a stator core fixedly disposed corresponding to a rotatable rotor on which a permanent magnet is fixed, to generate a rotating magnetic field which causes the rotor to rotate.

Abstract: A motor drive apparatus for driving a motor with power derived from a main power source, including a signal input device configured to input a start signal and a stop signal to initiate starting and stopping of the motor; a voltage regulator configured to output regulated electric power to the motor; and a semiconductor switching device disposed between the main power source and the voltage regulator, coupled to the signal input device, and configured to switch electric power from the main power source to the voltage regulator in accordance with the start signal input from the signal input device, and to shut off the electric power to the voltage regulator in accordance with the stop signal input from the signal input device.

Abstract: A rotor includes a hollow rotating shaft that is supported in a non-contact state by a radial self acting air bearing. The rotor also includes a contacting portion for positioning a rotating member in a rotating shaft direction that contacts with the rotating member from the rotating shaft direction. An engaging portion is included for positioning the rotating member in a direction perpendicular to the rotating shaft direction that engages with an inner surface of the rotating member. A holding portion is formed either in plural portions in a peripheral direction or as a single integrated portion that extends in the peripheral direction near the rotating member that is positioned by the contacting portion and the engaging portion, and that presses the rotating member from an opposite side of the contacting portion by deformation of one portion or a whole portion of the holding portion, and positions and holds the rotating member.

Abstract: A self-acting air bearing includes a housing, a shaft member supported in the housing, a cylindrical member which is installed around the shaft member coaxially and rotatably, and which rotates and generates a dynamic air pressure and thereby the cylindrical member is floatingly supported from the shaft member. In the bearing, concavities and convexes are formed at a same interval in a peripheral direction in either an outer peripheral surface of the shaft member or an inner peripheral surface of the cylindrical member, and a wave of one cycle between a beginning position of the concavity and an ending position of the convex is a harmonic wave. A bearing with high stability at high speed and high accuracy and which has high stability at high speed and low unbalance vibration can be achieved.

Abstract: A dynamic pressure pneumatic bearing device has a groove for generating a dynamic pressure and formed on an inner circumferential face of a rotating shaft or an outer circumferential face of a fixed shaft; each of these shafts being formed by an aluminum alloy; and a wear resisting film formed on each of the inner circumferential face and the outer circumferential face. Another dynamic pressure pneumatic bearing device is constructed by a rotating shaft having a cylindrical hollow and a fixed shaft inserted into this hollow. The fixed shaft has a bearing face opposed to an inner circumferential face of the rotating shaft and separated from this inner circumferential face with a predetermined clearance. Herringbone grooves for generating a dynamic pressure and recessed portions having the same depth as the herringbone grooves are formed on the bearing face.

Abstract: The current invention is directed to a high-speed optical deflector which includes a brushless motor operating in a high-temperature environment. The brushless motor components include rotatable parts made of various materials whose thermal expansion coefficients significantly vary. These rotational components include a steel rotor flange, a magnet rotor, and an aluminum shaft. To substantially eliminate rotational imbalance or vibration caused by the thermal expansion, the above described components are fixed with a certain adhesive which prevents these components from causing the rotational imbalance. A certain heat-resistant adhesive provides a sufficient structural strength to substantially minimize a rotational imbalance caused by the thermally expanding components in an operating temperature range.

Abstract: A closed type polygon scanner has a housing, a rotor which is rotatively supported to a rotating shaft fixed to the housing and which includes a polygon mirror, a motor which generates a magnetic force to the rotor and rotates the rotor, and a cover. The cover includes an outer peripheral portion fixed to an outer peripheral portion of the housing, and covers the rotor together with the housing. An opening is formed at a predetermined portion in the cover facing a mirror surface of the polygon mirror through which a laser beam passes, and a window member is fixed to the opening in closed state. An inner peripheral surface of the cover facing the mirror surface of the polygon mirror is formed cylindrically and almost coaxially to a rotating axis of the rotating shaft, and a width in the rotating axis direction of the opening is set to a predetermined width relative to a width of the polygon mirror so that turbulent air generated around the polygon mirror is reduced.

Abstract: A device for driving a DC motor includes a velocity control circuit generating a velocity control signal, a modulation circuit deriving a velocity control pulse signal having a pulse width modulated by the velocity control signal, a switching circuit, and a current-flow switching circuit. The switching circuit includes field effect transistors performing a switching operation, and a capacitor coupled between a power supply terminal and a reference potential. The capacitor absorbs a counter current caused in driving coils of the DC motor due to the switching operation.

Abstract: A polygon scanner has a lighter rotating shaft on which a polygon mirror is mounted, to prevent a positional deviation of the polygon mirror from the rotating shaft in high speed rotation, in which the rotating shaft is supported through a dynamic pressure air bearing on a fixed shaft, in which the polygon mirror and motor constituent members are mounted on the rotating shaft, and in which the rotating shaft and the polygon mirror are made of respective light weight materials matched with each other in coefficient of thermal expansion, for example of aluminum or an aluminum alloy. Further, an anodic oxide film is formed at least on a portion where the rotating shaft could contact with the fixed shaft, and floating means is provided for constantly floating the rotating shaft relative to the fixed shaft upward in an axial direction thereof.

Abstract: A polygon scanner has a lighter rotating shaft on which a polygon mirror is mounted, to prevent a positional deviation of the polygon mirror from the rotating shaft in high speed rotation, in which the rotating shaft is supported through a dynamic pressure air bearing on a fixed shaft, in which the polygon mirror and motor constituent members are mounted on the rotating shaft, and in which the rotating shaft and the polygon mirror are made of respective light weight materials matched with each other in coefficient of thermal expansion, for example of aluminum or an aluminum alloy. Further, an anodic oxide film is formed at least on a portion where the rotating shaft could contact with the fixed shaft, and floating means is provided for constantly floating the rotating shaft relative to the fixed shaft upward in an axial direction thereof.

Abstract: In a brushless motor, the number of coreless armature coils is set to 3n when the number of magnetic poles of a magnet for a magnetic field is set to 2n where n is a positive integer. An opening angle of each of the armature coils is set to 360/3n degrees. A notch portion is formed in an outer circumferential portion of the magnet for a magnetic field. A recessed portion is formed by this notch portion and an inner circumferential portion of a yoke. The recessed portion constitutes a groove for correcting a balance of each of the magnet for a magnetic field and a rotating body when this magnet and the rotating body are rotated. A motor housing and a harness are electrically connected to a printed board. The housing is connected to the ground through this harness and a harness for power. In this brushless motor, a magnetizing frequency is reduced and driving efficiency of a control circuit can improved when the brushless motor is rotated at a high speed.

Abstract: A face opposing type motor has a rotor yoke fixed to a hollow rotating shaft disposed in a non-contact bearing device; the non-contact bearing device having a fixed shaft inserted into the hollow rotating shaft; a rotor magnet held by the rotor yoke; and a driving coil substrate having a face opposed to the rotor magnet. The rotor yoke has a rotor magnet fitting portion fitted to an outer circumferential face of the rotor magnet so as to hold the rotor magnet by this rotor magnet fitting portion. In accordance with such a structure, it is possible to provide a reliable face opposing type motor having an excellent quality and cheaply manufactured by improving a system for holding a rotor magnet.

Abstract: An optical deflector of an air bearing type has a fixed shaft; a rotary shaft having a hollow portion fitted onto the fixed shaft; a support device disposed between an end portion of the fixed shaft and an end portion of the hollow portion opposite thereto and supporting the rotary shaft in an axial direction thereof; a radial air bearing formed between an inner circumferential face of the hollow portion and an outer circumferential face of the fixed shaft; a polygon mirror fixed to the rotary shaft; a driving device for rotating the rotary shaft; a device for deflecting light irradiated onto the polygon mirror by rotating the rotary shaft through the driving device; a device for forming a flange for fixing the polygon mirror thereto integrally with the rotary shaft; and a device for setting an upper end portion of the support device on a fixed shaft side thereof to be lower than an upper end face of the polygon mirror.