A duplex servomotor suitable for use in machine tools requiring automatic position control, feed control and the like, and other applications, which comprises a constant speed AC motor adapted to be coupled with a load to drive said load and a low-inertia DC servomotor adapted to be coupled with said load through speed reduction means and clutch means. The AC motor and DC motor are combined and arranged as a compact unit in a machine frame so that high-speed operation and low-speed operation can be independently transmitted to the load according to requirement.
A drive unit for direct drive of an information-storage disk comprises a collectorless D.C. external-rotor motor having a permanent-magnet rotor magnet arrangement of considerably reduced axial length. Electrostatic charge is removed from the rotor shaft by a metallic spring element which engages the shaft periphery from within the interior of the rotor housing. An electromagnetic braking arrangement is located interiorly of the housing. The packet of stator plates for the stator has an axial length shorter than that of the rotor magnet arrangement, but is provided at its axial end faces with skirted-rim flux-conducting elements whose peripheral skirt portions form useful-air-gap extensions in cooperation with the rotor magnet arrangement. The stator plate packet and associated skirted-rim flux-conducting elements may have cut-outs defining salient-pole structure; the skirt portions of the flux-conducting elements are provided with cut-outs at their leading ends serving to produce a reluctance torque component which, during rotor rotation, is shifted in time relative to the electromagnetic torque component attributable to the salient-pole configuration. The portion of the rotor structure which supports an information-storage disk has an annular recess accommodating a disk-holding magnet whose upper surface is slightly recessed relative to an annular magnetically conductive disk-supporting ridge of the rotor, the cross-sectional shape of the ridge being such as to establish a magnetic disk-holding force of exactly predetermined character despite tolerance-range variation of the coercive force of the holding magnet employed.
A disk-shaped armature for use in single-disk magnetic friction clutches has a disk-shaped body of iron which carries one or two friction generating facings consisting of sintered metal or metallic gauze impregnated with a synthetic plastic lubricant, such as polytetrafluorethylene. The facings extend beyond the end faces of the body and can form part of relatively thick rings which are recessed into the respective end faces or they may be applied to a single light metal ring which surrounds the body or to discrete light metal rings which are recessed into the respective end faces of the body.
A rotation detecting device for vehicle speedometers includes a housing, a magnetic induction device, and a magnetized rotor near the magnetic induction device. The rotor is connected through a coupling to a rotation source. A braking device forms a magnetic circuit between one end surface of the rotor and the housing, and brings the rotor into pressure contact with the housing by a magnetic attraction force generated in the magnetic circuit. Accordingly, a stable and proper braking torque can be applied against rotor vibration, to prevent a false output signal while idling. Furthermore, the amount of wear of a bearing for rotatably supporting a rotating shaft of the rotor can be reduced to improve durability of the rotation detecting device by reducing the braking torque during high-speed rotation of the rotor.
The starter comprises a flywheel rotated by an electric motor and an electromagnetic clutch for rendering the flywheel rigid with the crankshaft of the engine to be started. The flywheel carries on one side the armature of the motor and on the opposite side the inductor of the clutch. The motor inductor is carried by a flat disc which is parallel to the flywheel and defines a planar airgap of the motor. The flywheel has a part which is common to the magnetic circuits of the motor armature and the clutch inductor and has sufficient section to permit the circulation of the motor or clutch magnetic flux but is saturated by the circulation of the flux of the motor so that a remanent flux of the clutch will be cancelled out as soon as the magnetic flux of the motor is produced.
A drive unit for a hoist, an elevator in particular, with a motor (6), a transmission (2), a breaking means (4) and a housing (8) is characterized in that said motor (6) and said breaking means are together arranged in said housing (8). Furthermore, at least one part of said transmission (2) can be arranged in said housing (8) as mounted or built-in transmission so that said housing (8) for the largest part also forms the transmission housing.
