Rotor structure

A rotor structure including a rotor core provided with a central hole and a magnet hole formed in an outer circumferential portion, a permanent magnet mounted in the magnet hole, and a rotor shaft press-fit in the central hole,

• wherein the rotor structure further comprises:
• a magnetic flux leakage prevention hole formed in the rotor core to prevent leakage of magnetic flux from the permanent magnet;
• an outer-circumferential-side dovetail groove formed in an outer-circumferential-side inner wall of the magnetic flux leakage prevention hole on an outer circumferential side and an inner-circumferential-side dovetail groove formed, opposite the outer-circumferential-side dovetail groove, in an inner-circumferential-side inner wall of the magnetic flux leakage prevention hole on an inner circumferential side;
• and
• a non-magnetic bridge having both end portions engageable with the outer-circumferential-side dovetail groove and the inner-circumferential-side dovetail groove,
• wherein the non-magnetic bridge is formed with a chamfer at only one end face of both end faces of the non-magnetic bridge in an axial direction of the rotor shaft,
• wherein the non-magnetic bridge includes two or more non-magnetic bridges,
• wherein the rotor core is constituted by a plurality of stacked magnetic steel plates,
• wherein the chamfer has a length in an insertion direction which is longer than a thickness of one or two of the magnetic steel plates, and
• wherein the non-magnetic bridges are arranged so that the chamfers are located in alternate positions at one end face of the rotor core so that at least more than one of the non-magnetic bridges is in contact with the inner-circumferential-side dovetail groove or the outer-circumferential-side dovetail groove located at the end faces of the rotor core.