Stress distributing permanent magnet rotor geometry for electric machines

摘要

A rotor includes a cylindrical rotor core having an outer circumferential surface and a plurality of magnet insertion holes formed in the rotor core and arranged circumferential at a preset angular interval about the rotational axis of the rotor core. Each hole extends in a direction parallel to the rotational axis and has a cross section of a generally elongated slit. The elongated slit is curved concave relative to the circumferential surface and has a radially inward side, a radially outward side, and two ends that are respectively spaced apart from the circumferential surface by two bridges, wherein each bridge has thinner and thicker portions that are respectively positioned near the radially inward and outward sides. One or more permanent magnets are inserted in each hole and arranged to transfer centrifugal forces acting on the magnets during operation to portions of the bridges.