Rotor for electric motors

Abstract

Permanent magnet rotors for electric motors, particularly electric motors for use in compressors, improve the electromagnetic efficiency of the motor. The rotors can include retention of surface permanent magnets using one or more of retaining features on the motor and/or pole spacers interfacing with corresponding features on a rotor core, the use of a monolithic magnet in the rotor, and/or use of a carbon fiber sleeve. The rotor can include an eddy current shield, disposed on the rotor core, on a surface of the rotor, or located within a sleeve surrounding the rotor. The rotor can be sized such that an air-gap between the rotor and a stator of a motor using the rotor is a predetermined amount that reduces electromagnetic losses such as eddy current losses.

1 - 17 . (canceled) 
     
     
         18 . A rotor for an electric motor, comprising:
 a rotor core;   a plurality of permanent magnets;   a plurality of spacers; and   a sleeve configured to surround the rotor core, the plurality of permanent magnets, and the plurality of spacers, the sleeve including an eddy current shield located between an inner layer of the sleeve and an outer layer of the sleeve.   
     
     
         19 . The rotor of  claim 18 , wherein the rotor core includes a plurality of recesses and at least some of the plurality of permanent magnets include projections configured to be received within the recesses. 
     
     
         20 . The rotor of  claim 19 , wherein the recesses are grooves and the projections are bar-shaped. 
     
     
         21 . The rotor of  claim 19 , wherein the recesses are keyways and the projections are key projections, the keyways having a portion within the rotor core that is wider than an opening at a surface of the rotor core. 
     
     
         22 . The rotor of  claim 21 , wherein the keyways are trapezoidal in shape. 
     
     
         23 . The rotor of  claim 18 , wherein the body of the sleeve is a carbon fiber composite and the eddy current shield is copper. 
     
     
         24 . A rotor for an electric motor, comprising:
 a first rotor endpiece including a first channel;   a second rotor endpiece including a second channel; and   a permanent magnet including a magnet aperture, the permanent magnet secured between the first rotor endpiece and the second rotor endpiece; and   a shaft extending through the first channel, the magnet aperture, and the second channel, wherein the first rotor endpiece, the permanent magnet, and the second rotor endpiece are joined by the shaft, the shaft including a first flange sized such that the first flange cannot pass through the first channel and a second flange sized such that the second flange cannot pass through the second channel.   
     
     
         25 . The rotor of  claim 24 , further comprising a sleeve configured to surround a portion of the first rotor endpiece, a portion of the second rotor endpiece, and the permanent magnet. 
     
     
         26 . The rotor of  claim 25 , further comprising an eddy current shield located between an inner layer of the sleeve and an outer layer of the sleeve. 
     
     
         27 . The rotor of  claim 26 , wherein the body of the sleeve is a carbon fiber composite and the eddy current shield is copper. 
     
     
         28 . A rotor for an electric motor, comprising:
 a rotor core;   a plurality of permanent magnets; and   a plurality of spacers   wherein the rotor core includes a plurality of recesses and at least some of the plurality of permanent magnets include projections configured to be received within the recesses.   
     
     
         29 . The rotor of  claim 28 , wherein the recesses are grooves and the projections are bar-shaped. 
     
     
         30 . The rotor of  claim 28 , wherein the recesses are keyways and the projections are key projections, the keyways having a portion within the rotor core that is wider than an opening at a surface of the rotor core. 
     
     
         31 . The rotor of  claim 30 , wherein the keyways are trapezoidal in shape. 
     
     
         32 . The rotor of  claim 28 , further comprising a sleeve configured to surround the rotor core, the plurality of permanent magnets, and the plurality of spacers, the sleeve including an eddy current shield located between an inner layer of the sleeve and an outer layer of the sleeve.