Manufacturing method and composite powder metal rotor assembly for synchronous reluctance machine

• US 20030062791A1
• Filed: 10/03/2001
• Published: 04/03/2003
• Est. Priority Date: 10/03/2001
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Clase, Scott M., Stuart, Tom L., Reiter, Frederick B. Jr., Beard, Bradley D.
• Granted Patent: US 6,675,460 B2
• Time in Patent Office: Days
• US Class Current: 310/156.53
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 7/06 of composite workpieces or articles from parts, e.g. to form tipped tools B22F7/002 takes precedence
• CPC Class Codes: B22F 7/08 with one or more parts not made from powder B22F7/062 takes precedence
• CPC Class Codes: H02K 1/246 Variable reluctance rotors
• CPC Class Codes: H02K 15/02 of stator or rotor bodies
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/49011 Commutator or slip ring assembly
• CPC Class Codes: Y10T 29/49012 Rotor
• CPC Class Codes: Y10T 29/49075 including permanent magnet or core
• CPC Class Codes: Y10T 29/49076 From comminuted material

Abstract

A composite powder metal disk for a rotor assembly in a synchronous reluctance machine. The disk includes alternating regions of magnetically conducting powder metal and magnetically non-conducting powder metal compacted and sintered to a high density. A rotor assembly is also provided having a plurality of the composite powder metal disks mounted axially along a shaft with their magnetic configurations aligned. A method for making the composite powder metal disks is further provided including filling a die with the powder metals, compacting the powders, and sintering the compacted powders.

Claims

1. A method of making a powder metal rotor for a synchronous reluctance machine, the method comprising:

filling a disk-shaped die in one or more discrete first regions with a soft ferromagnetic powder metal;

filling the die in one or more discrete second regions with a non-ferromagnetic powder metal, the discrete second regions in alternating relation with the discrete first regions;

pressing the powders in the die to form a compacted powder metal disk; and

sintering the compacted powder metal disk to form a composite powder metal disk having one or more magnetically conducting segments and one or more magnetically non-conducting segments.

2. The method of claim 1, wherein the first and second regions are filled concurrently.

3. The method of claim 1, wherein the first and second regions are filled sequentially with the powder metal being pressed and sintered after each filling step.

4. The method of claim 1, wherein the soft ferromagnetic powder metal is Ni, Fe, Co or an alloy thereof.

5. The method of claim 1, wherein the soft ferromagnetic powder metal is a high purity iron powder with a minor addition of phosphorus.

6. The method of claim 1, wherein the non-ferromagnetic powder metal is an austenitic stainless steel.

7. The method of claim 1, wherein the non-ferromagnetic powder metal is an AISI 8000 series steel.

8. The method of claim 1, wherein the pressing comprises uniaxially pressing the powders in the die.

9. The method of claim 1, wherein the pressing comprises pre-heating the powders and pre-heating the die.

10. The method of claim 1, wherein, after the pressing, the compacted powder metal disk is de-lubricated at a first temperature, followed by sintering at a second temperature greater than the first temperature.

11. The method of claim 1, wherein the sintering is performed in a vacuum furnace having a controlled atmosphere.

12. The method of claim 1, wherein the sintering is performed in a belt furnace having a controlled atmosphere.

13. The method of claim 1 further comprising stacking a plurality of the composite powder metal disks axially along a shaft to form a powder metal rotor assembly.

14. A method of making a powder metal rotor for a synchronous reluctance machine, the method comprising:

filling a disk-shaped die in one or more discrete first regions with a soft ferromagnetic powder metal;

pressing the soft ferromagnetic powder metal in the die to form one or more compacted magnetically conducting segments;

sintering the compacted magnetically conducting segments;

filling the die in one or more discrete second regions with a non-ferromagnetic powder metal, the discrete second regions in alternating relation with the discrete first regions;

pressing the non-ferromagnetic powder metal in the die to form one or more compacted magnetically non-conducting segments; and

sintering the compacted magnetically non-conducting segments and the compacted and sintered conducting segments to form a composite powder metal disk having one or more magnetically conducting segments and one or more magnetically non-conducting segments.

15. The method of claim 14, wherein the ferromagnetic powder metal is Ni, Fe, Co or an alloy thereof.

16. The method of claim 14, wherein the soft ferromagnetic powder metal is a high purity iron powder with a minor addition of phosphorus.

17. The method of claim 14, wherein the non-ferromagnetic powder metal is an austenitic stainless steel.

18. The method of claim 14, wherein the non-ferromagnetic powder metal is an AISI 8000 series steel.

19. The method of claim 14, wherein each pressing comprises uniaxially pressing the powder in the die.

20. The method of claim 14, wherein each pressing comprises pre-heating the powder and pre-heating the die.

21. The method of claim 14, wherein, after the pressing, the compacted segments are de-lubricated at a first temperature, followed by sintering at a second temperature greater than the first temperature.

22. The method of claim 14, wherein each sintering is performed in a vacuum furnace having a controlled atmosphere.

23. The method of claim 14, wherein each sintering is performed in a belt furnace having a controlled atmosphere.

24. The method of claim 14 further comprising stacking a plurality of the composite powder metal disks axially along a shaft to form a powder metal rotor assembly.

25. A method of making a powder metal rotor for a synchronous reluctance machine, the method comprising:

concurrently filling a disk-shaped die in one or more first regions with a soft ferromagnetic powder metal and in one or more second regions with a non-ferromagnetic powder metal;

concurrently pressing the powders in the die to form a compacted powder metal disk; and

sintering the compacted powder metal disk to form a composite powder metal disk having one or more magnetically conducting segments and one or more magnetically non-conducting segments.

26. The method of claim 25, wherein the soft ferromagnetic powder metal is Ni, Fe, Co or an alloy thereof.

27. The method of claim 25, wherein the soft ferromagnetic powder metal is a high purity iron powder with a minor addition of phosphorus.

28. The method of claim 25, wherein the non-ferromagnetic powder metal is an austenitic stainless steel.

29. The method of claim 25, wherein the non-ferromagnetic powder metal is an AISI 8000 series steel.

30. The method of claim 25, wherein the pressing comprises uniaxially pressing the powders in the die.

31. The method of claim 25, wherein the pressing comprises pre-heating the powders and pre-heating the die.

32. The method of claim 25, wherein, after the pressing, the compacted powder metal disk is de-lubricated at a first temperature, followed by sintering at a second temperature greater than the first temperature.

33. The method of claim 25, wherein the sintering is performed in a vacuum furnace having a controlled atmosphere.

34. The method of claim 25, wherein the sintering is performed in a belt furnace having a controlled atmosphere.

35. The method of claim 25 further comprising stacking a plurality of the composite powder metal disks axially along a shaft to form a powder metal rotor assembly.

36. A powder metal disk for a rotor assembly in a synchronous reluctance machine, the disk comprising one or more magnetically conducting segments of pressed and sintered soft ferromagnetic powder metal, and one or more magnetically non-conducting segments of pressed and sintered non-ferromagnetic powder metal, the magnetically non-conducting segments in alternating relation to the magnetically conducting segments.

37. The disk of claim 36, comprising one magnetically conducting segment adjacent an interior circumferential surface of the disk and four or more circumferentially equally spaced magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

38. The disk of claim 36, comprising a magnetically non-conducting segment adjacent an interior circumferential surface of the disk and having four or more equiangularly spaced, radially extending arm portions defining axially extending channels there between, and a plurality of alternating, axially extending magnetically conducting and magnetically non-conducting segments in the channels.

39. The disk of claim 38, wherein the alternating segments are generally arcuate.

40. The disk of claim 36, comprising a magnetically conducting segment adjacent an interior circumferential surface of the disk and having four or more equiangularly spaced, radially extending arm portions defining axially extending channels there between, and a plurality of alternating, axially extending magnetically non-conducting and magnetically conducting segments in the channels.

41. The disk of claim 40, wherein the alternating segments are generally arcuate.

42. The disk of claim 36 comprising one magnetically conducting segment adjacent an interior circumferential surface of the disk and two opposed magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

43. The disk of claim 36 comprising a plurality of alternating magnetically conducting segments and magnetically non-conducting segments adjacent an interior circumferential surface of the disk and two opposed magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

44. The disk of claim 36 having sixteen poles equally spaced around the circumference of the disk.

45. The disk of claim 36, wherein the soft ferromagnetic powder metal is Ni, Fe, Co or an alloy thereof.

46. The disk of claim 36, wherein the soft ferromagnetic powder metal is a high purity iron powder with a minor addition of phosphorus.

47. The disk of claim 36, wherein the non-ferromagnetic powder metal is an austenitic stainless steel.

48. The disk of claim 36, wherein the non-ferromagnetic powder metal is an AISI 8000 series steel.

49. A powder metal rotor assembly for a synchronous reluctance machine, comprising:

a shaft; and

a plurality of powder metal composite disks axially stacked along and mounted to the shaft, each disk comprising;

one or more magnetically conducting segments comprising pressed and sintered soft ferromagnetic powder; and

one or more magnetically non-conducting segments in alternating relation to the magnetically conducting segments and comprising pressed and sintered non-ferromagnetic powder metal.

50. The assembly of claim 49, wherein the disks each have four or more poles aligned along the shaft.

51. The assembly of claim 50, wherein the disks comprise a magnetically conducting segment surrounding the shaft, and four or more circumferentially equally spaced magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

52. The assembly of claim 50, wherein the disks comprise a magnetically conducting segment surrounding the shaft and having four or more equiangularly spaced, radially extending arm portions defining axially extending channels there between, and a plurality of alternating, axially extending magnetically non-conducting and magnetically conducting segments in the channels.

53. The assembly of claim 52, wherein the alternating segments are generally arcuate.

54. The assembly of claim 50, wherein the disks comprise a magnetically non-conducting segment surrounding the shaft and having four or more equiangularly spaced, radially extending arm portions defining axially extending channels there between, and a plurality of alternating, axially extending magnetically conducting and magnetically non-conducting segments in the channels.

55. The assembly of claim 54, wherein the alternating segments are generally arcuate.

56. The assembly of claim 49, wherein the disks each have two poles aligned along the shaft.

57. The assembly of claim 56, wherein the disks comprise a magnetically conducting segment surrounding the shaft, and two opposed magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

58. The assembly of claim 56 comprising a plurality of alternating magnetically conducting segments and magnetically non-conducting segments adjacent an interior circumferential surface of the disk and two opposed magnetically non-conducting segments adjacent an exterior circumferential surface of the disk.

59. The assembly of claim 49 having sixteen poles equally spaced around the circumference of the disk.

60. The assembly of claim 49, wherein the soft ferromagnetic powder metal is Ni, Fe, Co or an alloy thereof.

61. The assembly of claim 49, wherein the soft ferromagnetic powder metal is a high purity iron powder with a minor addition of phosphorous.

62. The assembly of claim 49, wherein the non-ferromagnetic powder metal is an austenitic stainless steel.

63. The assembly of claim 49, wherein the non-ferromagnetic powder metal is an AISI 8000 series steel.