Composite powder metal rotor sleeve

A method of making an annular composite powder metal rotor sleeve for placing over an annular rotor core, the sleeve comprising a plurality of magnetically conducting segments in alternating relation with a plurality of magnetically non-conducting segments, the method comprising:

• placing a plurality of green-strength magnetically conducting segments adjacent a plurality of green-strength magnetically non-conducting segments in alternating relation to form a ring;
• adding powder metal between the segments;
• and
• sintering the segments and added powder metal whereby the segments are bonded together by the added powder metal to form the annular composite powder metal rotor sleeve.

A method of making an annular composite powder metal rotor sleeve for placing over an annular rotor core, the sleeve comprising a plurality of magnetically conducting segments in alternating relation with a plurality of magnetically non-conducting segments, the method comprising:

• filling a plurality of first regions in a ring-shaped die with a ferromagnetic powder metal;
• filling a plurality of second regions in the die with a non-ferromagnetic powder metal, the second regions in alternating relation with the first regions;
• pressing the powders in the die to form a compacted powder metal ring;
• and
• sintering the compacted powder metal ring to form the annular composite powder metal rotor sleeve.

A method of making an annular composite powder metal rotor sleeve for placing over an annular rotor core, the sleeve comprising a plurality of magnetically conducting segments in alternating relation with a plurality of magnetically non-conducting segments, the method comprising:

• injecting a ferromagnetic powder material from a first injection unit under heat and pressure into a plurality of first mold cavities in a ring-shaped mold, and allowing the ferromagnetic material to solidify;
• injecting a non-ferromagnetic powder material from a second injection unit under heat and pressure into a plurality of second mold cavities in the mold, the second mold cavities in alternating relation with the first mold cavities, and allowing the non-ferromagnetic material to solidify to thereby produce a composite injection molded green-strength ring;
• and
• sintering the composite ring.