DC motor with permanent magnet retaining structure

In a dynamoelectric machine having a cylindrical case with closed and open axial ends and a plurality of arcuate permanent magnets having circumferential and axial ends and being positioned circumferentially with the case, magnet retention apparatus adapted for easy drop-in assembly from the open end of the case and comprising:

• a magnet retention member comprising a ring fitting within the case adjacent its closed end and a plurality of resilient arms extending axially therefrom toward the open end of the case, each comprising two portions joined in a V-shaped cross section with an acute apex angle, one of which portions is fixed to the ring and the other of which free to move resiliently toward the one, the arms comprising a pair for each permanent magnet adapted to receive the magnet by its circumferential ends when inserted axially therebetween;
• an end cover adapted to close the open end of the case, the end cover including a plurality of fingers projecting axially inward therefrom for insertion between the resilient arms not having magnets therebetween, each finger having a tapered end for air in insertion between the arms, a constant width middle portion effective to compress the portions of resilient arms toward each other and against the magnet circumferential ends to retain the magnets radially and circumferentially between the arms and the case, each finger further having a wider base portion defining a pair of shoulders, one on either side of the finger, effective to engage the permanent magnets on axial ends thereof and bias the permanent magnets with their opposite axial ends into engagement with the rings, whereby the permanent magnets are axially retained between the end cover and the magnet retention member.