Laminated magnetic cores

• US 8,276,426 B2
• Filed: 03/20/2008
• Issued: 10/02/2012
• Est. Priority Date: 03/21/2007
• Status: Expired due to Fees

• Current Assignee: Magnetic Metals Corp. (Inductotherm Group)
• Original Assignee: Magnetic Metals Corp. (Inductotherm Group)
• Inventors: Musat, Rodica, Raneiro, Frank A., Rooney, Thomas H. Jr.
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US12/052,168
• Publication Number:
  US 20080229799A1
• Time in Patent Office: 1,657 Days
• Field of Search: 72/46, 723/33, 723/36, 723/63, 724/050.4, 724/24, 724/28, 724/43, 72/201, 72/202, 72/311.1, 727/00, 295/96, 295/98, 296/09, 310/43, 414/788.9, 414/791.6, 414/793.5, 324/545, 148/120, 335/216, 335/299
• US Class Current: 72/336
• CPC Class Codes: B21D 28/22 Notching the peripheries of circular blanks, e.g. laminations for dynamo-electric machines
• CPC Class Codes: H01F 41/0233 Manufacturing of magnetic circuits made from sheets magnetic cores made from sheets H01F27/245; soft magnetic alloys in the form of sheets H01F1/16
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49078 Laminated

Abstract

Laminations to be stacked as magnetic cores are produced from a very thin amorphous metal strip, using a punch press with accurate punch/die clearance. The laminations are collected on conveyor spindles or a transport rod or pipe, in either case being arranged without the need for substantial handling. Heat annealing and anti-vibration treatments can be applied along a conveying path. The laminations are grouped in a stack to define a core and are packaged or encapsulated in electrically nonconductive coverings. The finished core has advantageous electrical characteristics and low cost.

Claims

1. A method for forming a magnetic core comprising the steps of:

stamping an amorphous metal strip with a high-velocity punch and die to create one or more laminates, wherein the stamping includes advancing the high velocity punch and die at a speed between seven feet per second and twelve feet per second at a point of contact with the amorphous metal strip, for separating a laminate from the strip, the punch and die having a clearance based in part on a thickness of the amorphous metal strip;

grouping a pre-determined number of laminates in a stack; and

encapsulating the pre-determined number of stacked laminates in an electrically nonconductive container, the encased laminates forming a magnetic core.

2. The method of claim 1, further comprising the steps of:

collecting the one or more laminates on a cylindrical transport rod; and

advancing the one or more laminates along the cylindrical transport rod from the high-velocity punch and die to an encapsulation apparatus.

3. The method of claim 2, wherein during the advancing step the one or more laminates are heat treated to a temperature between about 700 degrees Fahrenheit to about 1080 degrees Fahrenheit.

4. The method of claim 2, wherein during the advancing step a vibration dampening agent is applied to the one or more laminates.

5. The method of claim 1, further comprising the steps of:

testing an electrical characteristic of the magnetic core; and

adjusting the number laminates in a stack based on a result of the testing.

6. The method of claim 1, further comprising the step of:

rejecting a magnetic core if a test result identifies the magnetic core as not having an electrical characteristic within a desired range.

7. The method of claim 1, further comprising the step of:

sorting one or more magnetic cores into groups according to an electrical characteristic of the magnetic cores.

8. The method of claim 1, wherein the punch and die clearance is approximately ten percent of the thickness of the amorphous metal strip.

9. The method of claim 1, further comprising the step of:

advancing the one or more laminates on a conveyor from the high velocity punch and die to an encapsulation apparatus.

10. The method of claim 3, wherein the laminates are heat treated in a nitrogen atmosphere.

11. The method of claim 3, wherein the laminates are heat treated for approximately twenty minutes to about 120 minutes.

12. A system comprising:

a punch press including a punch and die configured to stamp an amorphous metal sheet into one or more laminates, the punch and die having a clearance based in part on a thickness of the amorphous metal sheet, wherein the punch press is configured to advance the punch toward the die at a speed between seven feet per second and twelve feet per second at a point of contact with the amorphous metal sheet; and

an encapsulation apparatus configured to group the one or more laminates into a pre-determined number of laminates, the encapsulation apparatus further configured to encapsulate the pre-determined number of laminates in an electrically non-conductive container.

13. The system of claim 12, further comprising:

a conveyor disposed between the punch press and the encapsulation apparatus, the conveyor configured to receive the one or more laminates from the punch press and transport them in a processing direction towards the encapsulation apparatus.

14. The system of claim 12, wherein the clearance between the punch and the die is approximately ten percent of the thickness of the amorphous metal sheet.

15. The system of claim 13, further comprising:

an oven disposed along a length of the conveyor, the oven configured to heat treat the one or more laminates at a temperature between 700 degrees Fahrenheit and about 1080 degrees Fahrenheit.

16. The system of claim 15, wherein the one or more laminates are heat treated for about twenty minutes to about 120 minutes.

17. The system of claim 13, further comprising:

a spray apparatus disposed along a length of the conveyor, the spray apparatus configured to apply a vibration dampening agent to a surface of the one or more laminates.

18. The system of claim 12, further comprising:

a testing apparatus connected to the encapsulation apparatus, the testing apparatus configured to test a physical property of the encapsulated one or more laminates, the testing apparatus further configured to transmit a signal to the encapsulation apparatus such that the encapsulation apparatus adjusts the number of laminates in a group based on a result of the test.

19. A method for forming magnetic laminations from an amorphous metal strip, comprising the steps of:

feeding a sheet of work material comprising an amorphous metal strip between a punch and a die;

advancing the punch and die against the sheet of work material using an electromagnetic punch press for stamping a lamination from the work material, wherein the stamping includes engaging the punch and die with the work material at a velocity between about seven feet per second and about twelve feet per second at a point of contact with the work material.

20. The method of claim 19, further comprising annealing the amorphous metal strip prior to stamping such that the sheet of work material comprises a nanocrystalline soft metal strip from which the lamination is stamped.