Abstract: A position sensor using a soft magnetic core and a permanent magnet for detecting linear or rotary movements of a part. In one embodiment, a differential transformer is provided with corresponding windings 3, 4 and 5, which are wound on a tubular carrier member 2. Provided inside the carrier member 2 are a saturatable core 6 with a V-shaped crosssection section and a control magnet 8 which slides on the inner surfaces. The core 6 is partially saturated on the contact surfaces, so that a virtual air gap is produced, so that the transformation ratio between the windings 3 and 4, 5 is controlled as a function of position. Other versions employ flat and/or meandering coil arrangements and, in two instances, rotational relative motion.

Abstract: The invention relates to an axial fan with an essentially cylindrical outer housing and with a fan wheel which rotates therein and the hub of which is located on the rotor of an electric drive motor, the stator of the drive motor being held by webs extending on the delivery side relative to the outer housing. The vanes of the axial fan are radially twisted and possess a forward curvature with a camber varying from the hub cross-section to the outer cross-section. In order to achieve a pressure increase, at the same time with a reduction of the operating noise, the vanes have in the hub region a cross-section designed for a low flow per unit volume and small pressure increase, but in the outer region a cross-section designed for higher values of flow per unit volume and pressure increase.

Abstract: A flat portable fan with an impeller on a motor shaft and a commutatorless direct current motor is provided having a printed circuit board in the stator and an axially magnetized permanent magnet in the rotor. The circuit board comprises a printed circuit having electronic components of the fan drive and is made from an iron base material with an insulating layer, which carries the stator windings and an axial starting bearing for the rotor. The impeller is mounted in a cylindrical rotor mounting support and is driven by the axially magnetized permanent magnet. The iron base material and the permanent magnet substantially define a planar air gap.

Abstract: A disk memory drive includes a brushless drive outer rotor motor having an internal space and a stator with windings. The outer rotor coaxially encircles the stator and a substantially cylindrical air gap is defined between the stator and the rotor. The rotor includes permanent magnets and a hub fixedly connected with the magnet. A disk mounting section is provided on the hub for accommodating at least one storage disk positioned in a clear space, the mounting section being adapted to extend through a central aperture of the storage disk. The windings and the magnets interacting with the windings are disposed for at least half of the axial longitudinal dimension thereof within a space surrounded by the disk mounting section of the hub. Bearings rotatably mount the rotor and the hub.

Abstract: A permanent magnet excited motor is provided with a plurality of low circumferential hump-like protrusions on the face of each stator pole to partially decrease the air gap between the stator and rotor and act as so-called magnetic cams to exert a force on the rotor to smooth an otherwise uneven parasitic slot torque that occurs between the interaction of slot openings of the stator poles and the gaps between the permanent magnet poles of the rotor.

Abstract: An axial flow fan for ventilating electrical and electronic equipment includes a brushless, DC external rotor-type central drive motor. The stator is supported by a bearing tube formed of plastic, integrally molded with a mounting flange. In one embodiment, the fan casing forms part of the integral plastic molding.

Abstract: A method is disclosed for the low-loss regulation of a d.c. motor without commutator and of a semiconductor circuit in which, during a commutation phase at reduced motor power or rpm as given by a position indicator, the end transistors or one end transistor initially operates temporarily as a switch and thereafter temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.

Abstract: A disk storage drive is provided with a brushless drive motor having a stator with a winding. An external rotor coaxially surrounds the stator and is spaced therefrom by a substantially cylindrical air gap. The rotor includes a permanent magnet and a soft magnetic yoke. A hub is provided that is concentric to the yoke and is connected to the rotor for rotation therewith. The hub has a disk mounting portion on its outer peripheral surface that can be passed through the central opening of a standardized storage disk for mounting the storage disks for rotation therewith. At least half of the axial longitudinal dimension of the stator winding and the rotor magnet interacting therewith is housed within the disk mounting portion of the hub. The hub is made from a non-ferromagnetic material that is suitable for storage drive clean chamber use after dimensional finishing of the hub.

Abstract: A step motor which, in addition to an exciter system for step-by-step movement, is provided with a further exciter system. As a result of the direct or indirect influence of the magnetic field generated by the secondary exciter system on the rotor which is supported so as to be able to move in an axial direction with respect to the stator, the rotor can be induced to move in a direction perpendicular to its step-by-step rotary motion, as well. Both exciter systems can be energized independently of one another, so that step-by-step rotary movement can be performed at any axial position of the rotor, and the rotor can be made to move in an axial direction during its rotary movement, as well as when it is at rest.

Abstract: A low noise brushless dc motor has a rotor with a permanent magnet and a stator with a bearing system mounting a shaft for rotating the rotor. The bearing system includes at least one axially extending bearing surface that terminates in axially spaced apart ends defining the outer axial limits of the bearing surface. Magnetic components of the rotor and the stator define a magnetic circuit. the magnetic components have an eccentricity creating an asymmetry in the magnetic circuit that causes a resultant lateral magnetic force to be applied on the shaft at a point axially inside the outer axial limits of the bearing surface, whereby the shaft exerts a pressure along the bearing surface between both ends of the bearing surface in a direction perpendicular to the rotor axis.

Abstract: A permanent magnet excited electric motor is provided with a low circumferential hump-like protrusion on the face of each electromagnetic pole to partially decrease the air gap between the stator and rotor and act as a so-called magnetic cam to exert a force on the rotor to smooth an otherwise uneven parasitic slot torque that occurs between the interaction of slot openings of the electromagnetic poles and the gaps between the permanent magnet poles.

Abstract: A disk storage drive is provided with a brushless drive motor having a stator with a winding. An external rotor coaxially surrounds the stator and is spaced therefrom by a substantially cylindrical air gap. The rotor includes a permanent magnet and a soft magnetic yoke. A hub is provided that is concentric to the yoke and is connected to the rotor for rotation therewith. The hub has a disk mounting portion on its outer peripheral surface that can be passed through the central opening of a standardized storage disk for mounting the storage disks for rotation therewith. At least half of the axial longitudinal dimension of the stator winding and the rotor magnet interacting therewith is housed within the disk mounting portion of the hub. The hub is made from a non-ferromagnetic material that is suitable for storage drive clean chamber use after dimensional finishing of the hub.

Abstract: A method is disclosed for the low-loss regulation of a d.c. motor without commutator and of a semiconductor circuit in which, during a commutation phase at reduced motor power or rpm as given by a position indicator, the end transistors or one end transistor initially operates temporarily as a switch and thereafter temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.

Abstract: An axial flow fan for ventilating electrical and electronic equipment includes a brushless, DC external rotor-type central drive motor wherein the rotor is covered by a thermally-insulative impeller. The rotor is supported by a bearing tube formed of plastic, integrally moulded with a mounting flange. In one embodiment, the fan casing forms part of the integral plastic molding.

Abstract: A seal includes a magnetic circuit having a permanent magnet providing excitation. A rotatable shaft has a straight cylindrical outer surface and is supported in a ball bearing system. A magnetically conductive bearing ring is mounted on the shaft immediately adjacent one end of the bearing system. The bearing ring has two radial portions of different thicknesses, the outer portion being thinner than the inner portion adjacent the shaft. A permanent magnet ring is located adjacent the bearing ring on the side opposite the bearing system. A labyrinth gap is defined between the bearing system and the permanent magnet ring on both sides of the bearing ring radially extending therebetween, and a ring pole is located axially adjacent the permanent magnet ring on the opposite side of the bearing system. An active pole gap is defined between the inner diameter of the ring pole and the shaft and is filled with a magnetically conductive fluid, the gap being essentially in series with the labyrinth gap.

Abstract: A disk storage drive is provided with a brushless drive motor having a stator with a winding. An external rotor coaxially surrounds the stator and is spaced therefrom by a substantially cylindrical air gap. The rotor includes a permanent magnet and a soft magnetic yoke. A hub is provided that is concentric to the yoke and is connected to the rotor for rotation therewith. The hub has a disk mounting portion on its outer peripheral surface that can be passed through the central opening of a standardized storage disk for mounting the storage disks for rotation therewith. At least half of the axial longitudinal dimension of the stator winding and the rotor magnet interacting therewith is housed within the disk mounting portion of the hub. The hub is made from a non-ferromagnetic material that is suitable for storage drive clean chamber use after dimensional finishing of the hub.

Abstract: In a coreless coil type cylindrical air gap dc motor, a ring flange is provided. Connections to the coil are formed in the ring flange by conductor paths in the form of stamped metal strips lying in a plane. The conductor paths in turn have connecting tongues which are directed radially with respect to the ring flange.

Abstract: Electric motor with a substantially cylindrical air gap between the stator and the rotor, the stator being fitted to a bearing support for the rotor shaft bearing. In order to reduce noise emissions, the stator is connected to the bearing support by means of an elastic damper and the stator and bearing support are separated from one another by an air gap adjacent at least part of their facing faces.

Abstract: Disclosed is an arrangement for providing an electrical connection to the enamelled wire of a coil of an electrical motor. The arrangement includes a circuit board carrying at least one conductive component such as an electrical trace on the surface of the circuit board. A conductive pin-type contact, also carried by the circuit board, is electrically connected to the conductive component. An insulating body is carried by the electrical motor and includes passageways for receiving at least two pin-receiving receptacle terminals. The receptacle terminals have inwardly-extending rib members for engaging the enamelled wire when the enamelled wire and the pin-type contact are inserted therein. The rib members are operative to penetrate the enamel covering to establish electrical contact with the wire.

Abstract: The invention relates to a brushless direct current motor system that includes an outer rotor receiving a load member such as a fan wheel having a plurality of blades. An axial extension of the rotor functions as a drive boss whose diameter is independent of the diameter of the motor stator core and is step-wise smaller in diameter at its outer closed end than at its inner opened end.