Patent ID: 7339290
Filing Date: 2008-03-04
Classification: H02K

Abstract:
1. A linear motor having a moving element and a stator comprising: two inductors formed of a magnetic material; each of said at least two inductors including a tooth row at each of both sides in a width direction orthogonal to a moving direction of the moving element, said tooth row being formed of a plurality of teeth provided at predetermined pitch τ1 in said moving direction, said two inductors being arranged in parallel and spaced apart from each other by a predetermined spacing in said width direction orthogonal to said moving direction, an armature having an armature iron core, three armature windings, and six permanent magnet rows including a plurality of permanent magnets being provided at a predetermined pitch τ2 in said moving direction, said permanent magnets being so arranged that different polarities alternately appear in said moving direction, wherein said armature iron core includes three magnet pole portions and two yoke portions each for magnetically coupling adjacent two of said three magnetic pole portions, and said three magnetic pole portions is spaced apart from each other in parallel by a predetermined spacing so that each of said inductors is positioned within the spacing, and said armature iron core being constituted by a plurality of electromagnetic steel plates laminated in said moving direction, each of three magnetic pole portions has one or two opposed surfaces opposing said tooth row of each of said inductors, and each of four permanent magnet rows is provided on each of said opposed surfaces, each of said three armature windings is wound around each of said three magnetic pole portions so that magnetic flux is generated between said plurality of permanent magnets forming said permanent magnetic pole row and said tooth row opposing said permanent magnet pole row, geometrical phase difference between said two tooth rows provided at each of said two inductors in terms of an electrical angle is 120 degrees, geometrical phase difference between said two inductors in terms of an electrical angle is 0 degrees, geometrical phase difference between said two permanent magnet rows facing said two tooth rows provided at said inductor in terms of an electrical angle is 120 degrees, geometrical phase difference between said two permanent magnet rows provided at said inductor in terms of an electrical angle is zero degrees, either of said two inductors or said armature is used as said moving element and other of said two inductors or said armature is used as said stator.