Abstract:
A disk storage device including a housing surrounding a clean chamber, at least one storage disk having a central opening, at least one data head mounted on the housing for movement in operative relationship with the disk within the clean chamber, and motor elements for rotating the disk within the clean chamber. The motor elements include a rotatable member positioned within the clean chamber. The rotatable member has a cylindrical outer surface portion that extends into the central opening of the storage disk and is supported by a shaft and bearing system. A stator including magnetically active parts is mounted on a support member, which also supports the shaft and bearing system. The stator has a magnetic flux-producing section having poles positioned on the same side of the support member as the rotatable member. The rotatable member includes a cylindrically-shaped magnetic flux-producing and conducting element including a ferromagnetic ring and an annular permanent magnet spaced from the poles of the stator by a substantially cylindrical air gap. Further, the outside diameter of the cylindrically-shaped magnetic flux-producing and conducting element is larger than the diameter of the central opening of the storage disk.
Abstract:
A brushless DC drive motor with an external rotor has three pole shoes on a substantially ring-shaped stator for each two poles on the rotor. The stator winding is commutated by a three-phase commutation network in such a fashion that first, second and third networks in the stator winding are cyclically connected to an external DC source in accordance with rotor position. Each of the networks comprises at least one stator coil wrapped around a neck of a single corresponding one of the pole shoes.
Abstract:
A disk storage device having a clean chamber for a storage disk having a central opening is provided with a brushless drive motor. The drive motor includes a stator and a winding on the stator and further includes a shaft aligned with the rotation axis of said motor, and a magnetically conducting member supported for rotation about the rotation axis and having an inner wall coaxially surrounding the stator. A magnet fixed to the inner wall of the magnetically conducting member is radially spaced from the stator. The disk storage device further includes a hub positioned within the clean chamber and contiguous with the magnetically conducting member so that the hub and the magnetically conducting member together form an outer rotor of the drive motor. The outer rotor has a radially extending flange having a surface which supports said storage disk. A support member contiguous with a portion of a partition of the clean chamber supports the shaft and has a recess receiving a portion of said radially extending flange, whereby the spacing between opposing walls of the clean chamber is reduced. Further, the magnet is spaced from the stator by a substantially cylindrical air gap having a diameter greater than the diameter of the central opening of the storage disk.
Abstract:
A brushless direct current motor is energized by a power stage. Switches of the power stage are selectively switched by an electronic control device. In order to determine the correct commutation pattern, without using rotor position indicators such as Hall effect devices, the control device is arranged to sample the power fed to the motor. The samples, each responsive to a test signal or normal energization pulses received by the motor, in a ordered sequence define an analogue function whose parameters can be determined by mathematical analysis. The analysis applied to the samples derives the necessary commutation information and the energization signals in a rapid manner by employing a vector or complex number addition based on functions dependent on variable inductance in the operation of the motor.
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 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:
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:
A linear motor unit includes a stator having on outer flux-carrying structure and an inner flux-carrying structure, and an armature arranged for travel along the length of the inner flux-carrying structure. The inner flux-carrying structure comprises an elongated rod. The armature slidably positioned along these rods carries a number of coils spaced one from another in the direction of elongation of the rod and surrounding the rod. A plurality of sets of permanent magnets are concentrically positioned within the outer flux-carrying structure which is arranged in a form of two tubular elongated members. The permanent magnets in each set are radially positioned with respect to the rods and located one opposite to another. Preferably successive ones of the sets of magnets have an alternate polarity. The coils are energized periodically and in a cyclical sequence to provide a motive force for the movement of armature along the parallel rods.
Abstract:
An electromotive drive is provided, especially for the pump of a power-assisted steering system of a motor vehicle. The drive includes a housing (3) with a bearing journal (15) in which the shaft (18) of a rotor (9) is rotationally mounted. The drive also includes a stator (7) having drive windings. The bearing journal (15) extends through said stator and supports it. The stator (7) is supported by the bearing journal (15), substantially in the transversal direction only. The stator (7) is coupled with the remaining housing (3) in a rotationally fixed manner, so as to transmit the engine torque. The arrangement dramatically reduces disturbing noises which occur especially when the motor is operated at full load and which are caused by relatively high-frequency torque variations.