US 4,072,881 A · Axial-air-gap type semiconductor electric motor

Abstract

An axial-air-gap type semiconductor motor has a disc-shaped rotor, a pair of disc-shaped armatures coaxially located adjacent the opposite faces of the rotor with air-gaps therebetween, a system for detecting the rotational position of the rotor for generating an output proportional to the rotating speed of the rotor, and a semiconductor circuit operable in response to the output from the position-detecting system for controlling the armature current to effect constant-speed control of the rotation of the rotor. The rotor includes a field magnet. Two groups of armature coils are mounted on the face of each of the armature discs facing the rotor. The position-detecting system includes a control band which includes a plurality of control sections and which is synchronously rotatable with the rotor, and detectors which are located at fixed positions along the control band for generating an output in response to the control sections of the control band. The control band may be provided integrally around the periphery of the rotor. Induction coils are provided, each being affixed to the central portion of each of the armature coils. The induction coils generate a three-phase output proportional to the rotating speed of the rotor. The output from the induction coils is rectified by a rectifying circuit and is applied to the current control circuit to provide a constant-speed control for the rotor.

Claims17

Dependent claims

An axial-air-gap type semiconductor motor comprising:

a disc-shaped rotor fixed coaxially to a shaft mounted for rotation to a casing for the motor, the disc of said rotor comprising a field magnet having a plurality of magnetic poles formed of portions of said disc located in the circular direction at equal pitches, said magnetic poles being magnetized alternately in opposite polarization directions along the rotating axis of said rotor;
a first magnetic-material disc and a second magnetic material disc coaxially located respectively adjacent the opposite faces of said rotor with air-gaps therebetween and being fixed to said casing;
a plurality of armature coils arranged in turn at angular pitches of a predetermined proportion of the angular width of the pole of said field magnet, odd-numbered ones of said armature coils being affixed to the face of said first magnetic-material disc which faces said rotor, and even-numbered ones of said armature coils being affixed to the face of said second magnetic-material disc which faces said rotor;
a control band rotatable synchronously with said rotor;
position-detector means located at fixed positions along the rotating path of said control band for detecting rotational position of said rotor in cooperation with said control band to generate an output corresponding to the rotational position of said rotor;
and
a current control semiconductor circuit for controlling, in response to the output from said position-detector means, current flowing through said armature coils.

4 more elements

An axial-air-gap type semiconductor motor comprising:

a disc-shaped rotor fixed coaxially to a shaft mounted for rotation to a casing for the motor, the disc of said rotor constituting a field magnet having a plurality of magnetic poles formed of portions of said disc which take their places in the circular direction at equal angular pitches and have been magnetized alternately in opposite polarization directions along the rotating axis of said rotor;
a first magnetic-material disc and a second magnetic-material disc coaxially located respectively adjacent the opposite faces of said rotor with air-gaps therebetween and being fixed to said casing;
a plurality of armature coils arranged in turn at angular pitches of 2/3 of the angular width of the pole of said field magnet, odd-numbered ones of said armature coils being affixed to the face of said first magnetic-material disc which faces said rotor, and even-numbered ones of said armature coils being affixed to the face of said second magnetic-material disc which faces said rotor;
a control band rotatable synchronously with said rotor;
position detector means located at fixed positions along the rotating path of said control band for, through said control band, detecting rotational position of said rotor to generate an output corresponding to the rotational position of said rotor;
a current control semiconductor circuit for controlling, in response to the output from said position-detector means, current flowing through said armature coils;
induction coils affixed respectively at portions which are surrounded respectively by the windings of said armature coils for generating, in accordance with rotation of said rotor, a three-phase alternating current;
and
a circuit for rectifying the alternating current from said induction coils and applying the resultant rectified current to said current control semiconductor circuit thereby to serve for the controlling of current flowing through said armature coils.

6 more elements

Dependencies are inferred from the claim text.

Axial-air-gap type semiconductor electric motor

Life of this patent

Axial-air-gap type semiconductor electric motor

Life of this patent

Abstract

Claims17