Manufacturing method and composite powder metal rotor assembly for circumferential type interior permanent magnet machine

A method of making a powder metal rotor for a circumferential type interior permanent magnet machine, the method comprising:

• filling an inner annular region of a disk-shaped die with a soft ferromagnetic powder metal;
• filling a plurality of discrete first regions within an outer annular region of the die with a non-ferromagnetic powder metal so as to leave spaces between each discrete first region;
• filling a plurality of discrete second regions in the outer annular region between the first regions with a soft ferromagnetic powder metal so as to maintain a radially inner circumferentially extending space between each discrete first region;
• pressing the powders in the die to form a compacted powder metal disk;
• sintering the compacted powder metal disk;
• and
• providing permanent magnets in the radially inner circumferentially extending spaces between the discrete first regions of the outer annular region in an arrangement of alternating polarity to form a composite powder metal disk having an inner annular magnetically conducting segment and an outer annular permanent magnet segment of a plurality of alternating polarity permanent magnets separated by magnetically non-conducting barrier segments and radially embedded by magnetically conducting segments.

A method of making a powder metal rotor for a circumferential type interior permanent magnet machine, the method comprising:

• filling an inner annular region and a plurality of first portions of an outer annular region of a disk-shaped die with a soft ferromagnetic powder metal;
• pressing and sintering the soft ferromagnetic powder metal in the die to form a compacted and sintered inner annular magnetically conducting segment and a plurality of compacted and sintered outer magnetically conducting segments;
• filling a plurality of second portions in the outer annular region of the die with a non-ferromagnetic powder metal, the second portions being in alternating relation with the outer magnetically conducting segments;
• optionally filling a plurality of third portions in the outer annular region of the die with a non-ferromagnetic powder metal, the third portions radially extending through an intermediate portion of each first portion;
• pressing the non-ferromagnetic powder metal in the die to form a plurality of compacted magnetically non-conducting barrier segments and optional bridge segments;
• sintering the compacted magnetically non-conducting barrier and optional bridge segments and the compacted and sintered inner annular and outer magnetically conducting segments;
• and
• providing circumferentially extending permanent magnets in a plurality of radially inner fourth portions in the outer annular region between the magnetically non-conducting barrier segments in an arrangement of alternating polarity to form a composite powder metal disk having an inner annular magnetically conducting segment and an outer annular permanent magnet segment of a plurality of alternating polarity permanent magnets separated by magnetically non-conducting barrier segments and radially embedded by magnetically conducting segments with optional intermediate magnetically non-conducting bridge segments.

A powder metal disk for a rotor assembly in a circumferential type interior permanent magnet machine, the disk comprising:

• an inner annular magnetically conducting segment;
• and
• an outer annular permanent magnet segment comprising alternating magnetically non-conducting barrier segments and embedded circumferentially extending permanent magnets, the permanent magnets alternating in polarity, and radially outer magnetically conducting segments embedding the permanent magnets, each having an optional intermediate magnetically non-conducting bridge segment extending radially from the permanent magnet to an outer circumferential surface of the disk,
• wherein the magnetically non-conducting barrier segments and optional bridge segments comprise pressed and sintered non-ferromagnetic powder metal and the inner annular and outer magnetically conducting segments comprise pressed and sintered soft ferromagnetic powder metal.

A powder metal rotor assembly for a circumferential type interior permanent magnet machine, comprising:

• a shaft;
• and
• a plurality of composite powder metal disks axially stacked along and bonded to the shaft, each disk comprising:
• (a) an inner annular magnetically conducting segment;
• and
• (b) an outer annular permanent magnet segment comprising alternating magnetically non-conducting barrier segments and embedded circumferentially extending permanent magnets, the permanent magnets alternating in polarity, and radially outer magnetically conducting segments embedding the permanent magnets, each having an intermediate magnetically non-conducting bridge segment extending radially from the permanent magnet to an outer circumferential surface of the disk,
• wherein the magnetically non-conducting barrier segments and bridge segments comprise pressed and sintered non-ferromagnetic powder metal and the inner annular and outer magnetically conducting segments comprise pressed and sintered soft ferromagnetic powder metal.