Die Cast Rotor With Steel End Rings to Contain Aluminum

Abstract

A rotor for an electrical inductor motor or an induction generator includes a core having spaces formed in the core. The rotor also has a first end ring. The first end ring has a first hub portion. A first ring is connected to the first hub portion by first spokes. The rotor also has a second end ring. The second end ring has a second hub portion. A second ring is connected to the second hub portion by second spokes. The first end ring is secured to the core. The second end ring is rotated a predetermined amount so the first spokes are misaligned with the second spokes. The second end ring is connected to the first end ring and the core. The core, the first end ring and the second end ring form a substrate. An aluminum conductor is cast to the substrate. The aluminum conductor fills in the spaces and around the first and second spokes to form a cast rotor.

1 . An electric machine including a stator and a rotor, the rotor comprising:
 a core including a plurality of spaces formed in the core;   a first end ring including a first hub portion with a first ring, the first ring being connected to the first hub portion by a plurality of first spokes;   the first end ring and the core forming a substrate; and   a conductor being attached to the substrate, the conductor filling in the plurality of spaces formed in the core and extending around the plurality of first spokes to form the rotor.   
   
   
       2 . The electric machine of  claim 1 , further comprising a second end ring including a second hub portion with a second ring, the second ring being connected to the second hub portion by a plurality of second spokes;
 the first end ring being secured to the core;   the second end ring being rotated a predetermined amount so the plurality of first spokes are misaligned with the plurality of second spokes;   the second end ring being connected to the first end ring;   the core, first end ring and the second end ring forming the substrate; and   wherein the conductor also extends around the plurality of second spokes to form the rotor.   
   
   
       3 . The electric machine of  claim 2 , wherein at least one of the first end ring and the second end ring is formed from steel. 
   
   
       4 . The electric machine of  claim 3 , wherein the conductor is formed from aluminum. 
   
   
       5 . The electric machine of  claim 4 , wherein the first end ring includes a plurality of pockets between the spokes, and wherein the pockets reduce a hoop stress caused from thermal fatigue during rotation of the rotor measured relative to a rotor formed from pure aluminum. 
   
   
       6 . The electric machine of  claim 4 , wherein the second end ring includes a plurality of pockets between the spokes, and wherein the pockets reduce a hoop stress caused from thermal fatigue during rotation of the rotor measured relative to a rotor formed from pure aluminum. 
   
   
       7 . The electric machine of  claim 2 , wherein the first end ring or the second end ring is made from a stamped material. 
   
   
       8 . The electric machine of  claim 2 , wherein at least one of the first and the second end rings is formed from a ferrous material. 
   
   
       9 . The electric machine of  claim 4 , wherein at least one of the first and the second end rings is formed from a non ferrous material and a ferrous material, wherein the non-ferrous material is adapted to separate the aluminum conductor from the core. 
   
   
       10 . The electric machine of  claim 2 , wherein at least one of the first and the second end rings is formed having a varying thickness. 
   
   
       11 . The electric machine of  claim 2 , wherein at least one of the first and the second end rings is formed from a laminate. 
   
   
       12 . The electric machine of  claim 2 , wherein either of the plurality of first spokes and the plurality of second spokes form a total number of spokes, and the total number is related to a rotor length. 
   
   
       13 . The electric machine of  claim 2 , wherein either of the plurality of first spokes and the plurality of second spokes form a total number of spokes, and the total number is related to a rotor geometry. 
   
   
       14 . A method of manufacturing a rotor comprising:
 forming a core with a plurality of spaces formed in the core;   connecting a first end plate to an end of the core, the first end plate including a first hub connected to a first ring by a plurality of first spokes;   connecting a second end plate to the first end plate, the second end plate including a second hub connected to a second ring by a plurality of second spokes;   forming a substrate from the end plates and the core;   staggering the plurality of second spokes from the plurality of first spokes to form pockets being defined between the plurality of first and second spokes; and   casting a conductor to the substrate with the conductor flowing into the plurality of spaces of the core and the pockets to form a cast rotor.   
   
   
       15 . The method of  claim 14 , further comprising providing a stator, wherein the rotor is rotatably mounted in the stator to form an electric machine. 
   
   
       16 . The method of  claim 14 , wherein at least one of the first and the second end rings is comprised of steel. 
   
   
       17 . The method of  claim 14 , wherein the conductor is comprised of aluminum. 
   
   
       18 . The method of  claim 14 , wherein the first end ring is comprised of nonferrous material, and the second end ring is comprised of ferrous material, and wherein the first and the second end rings form a laminate. 
   
   
       19 . The method of  claim 18 , wherein the laminated end ring has a varying thickness. 
   
   
       20 . The method of  claim 14 , wherein at least one of the first and the second end rings is formed by a stamping operation. 
   
   
       21 . The method of  claim 14 , wherein the first end ring is disposed between the second end ring and the core, and the first end ring is comprised of a material that forms a buffer between the second end ring and the core. 
   
   
       22 . An end ring for a rotor comprising:
 a first member including a first ring being connected to a first hub by a plurality of first spokes; and   a second member being connected to the first member, the second member including a second ring being connected to a second hub by a plurality of second spokes, the first spokes being offset from the second spokes by a predetermined amount to form pockets therebetween, and a material different from that of at least one of the first member and the second member extends into the pockets, wherein the first member and the second member reduce a hoop stress caused by thermal fatigue of the rotor that is attributed to the material during cyclic operation of the rotor.