US 4,307,309 AGranted

Brushless dynamoelectric machine

OwnerEdward L. Barrettinventor

Life of this patent

Estimating the term…

Loading patent…

Abstract

A brushless alternator or like dynamoelectric machine, particularly adapted for use in a vehicle, comprising a field coil mounted on the center leg of a stationary core, a rotor shaft extending through the center leg of the core, a first, disc-shaped rotor member mounted on the shaft and facing the center leg of the core across a first large-area axial air gap and having a first set of radially projecting rotor poles, and a second, annular rotor member mounted on the first rotor member, facing an outer flange portion of the core across a second large-area axial air gap and having a second set of axially projecting rotor poles interleaved one-for-one with the first set. The two sets of rotor poles have pole faces aligned in a common radial plane facing an annular array of stator poles across a third large-area axial air gap arranged to balance the magnetic attraction forces to which the rotor is subjected; the stator poles are of laminated construction, formed in pairs and mounted in an annular laminated stator that is in turn mounted on the core by non-magnetic means affording a sealed housing for the machine. The coils of the stator winding are wound in an even number of layers, alternately outside-in and inside-out, with the corresponding layers of adjacent coils interconnected, to afford maximum current capacity in coils of minimum axial length, keeping the axial length of the stator poles to a minimum.

Claims11

Dependent claims

A brushless alternator or like dynamoelectric machine comprising:

a stationary, annular, magnetic excitation core including a tubular central portion, an integral wall portion extending radially outwardly one end of the central portion, a skirt portion extending from the outer rim of the wall portion back over the central portion in spaced coaxial relation thereto, and a flange portion extending radially outwardly from the free end of the skirt portion;
an excitation coil mounted in encompassing relation to the central portion of the core;
a rotor shaft extending through and journalled in the central portion of the core;
a first, generally disc-shaped rotor member affixed to the shaft and facing the central portion of the core across a first large-area axial air gap;
a first set of rotor poles projecting radially outwardly of the first rotor member;
a second, annular rotor member, mounted on the first rotor member by non-magnetic mounting means for rotation therewith and facing the flange portion of the core across a second large-area axial air gap;
a second set of rotor poles projecting axially from the second rotor member into one-for-one interleaved relation with the first set of rotor poles,
the rotor poles of both sets having pole faces aligned in a common radial plane facing axially outwardly from the core;
a stator including an annular base, a plurality of stator poles projecting axially from the stator base and having pole faces aligned in a common radial plane, and a winding mounted on the stator poles;
and non-magnetic stator mounting means for mounting the stator on the core with the stator pole faces facing the rotor pole faces across a third large-area axial air gap, the magnetic attraction between the rotor and the core across the first two air gaps being opposite in direction to and generally balanced by the magnetic attraction between the rotor and the stator across the third air gap.

7 more elements

Dependencies are inferred from the claim text.