System and method of making a cast induction rotor assembly having conductive bars

Patent metadata

Field	Value
Publication number	US-12206285-B2
Application number	US-202318174879-A
Country	US
Kind code	B2
Filing date	Feb 27, 2023
Priority date	Feb 27, 2023
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

An induction rotor assembly having conductive bars is provided. The assembly comprises a lamination stack comprising a body having a first end and second ends to define a longitudinal axis. The body has an outer circumferential portion extending from the first end to the second end. The outer portion has a plurality of walls defining open slots formed from the first end through the second end. The assembly further comprises a first ring disposed on the first end and a second ring disposed on the second end. The assembly further comprises a plurality of conductive bars extending between the first and second rings. Each conductive bar is disposed in one of the slots such that the respective conductive bar is in contact with the lamination stack and connects the first and second rings. Each bar comprises an inner portion and a conductive outer skin disposed about the inner portion.

First claim

What is claimed is:

1. A cast induction rotor assembly having conductive bars, the cast induction rotor assembly comprising:
a lamination stack comprising a body having a first end and an opposing second end to define a longitudinal axis, the body having an outer circumferential portion extending from the first end to the second end along the longitudinal axis, the outer circumferential portion having a plurality of walls defining open slots formed therethrough from the first end through the second end;
a first ring disposed on the first end;
a second ring disposed on the second end; and
a plurality of conductive bars extending between the first ring and the second ring, each conductive bar disposed in one of the open slots such that the respective conductive bar is in contact with the lamination stack, each conductive bar connecting the first and second rings, each conductive bar comprising an inner portion and an outer skin disposed about the inner portion, the inner portion having a first width, the outer skin having carbon nanotubes disposed thereon in a predetermined orientation for conductivity, the outer skin having a second width to define a width ratio of the first width to the second width of between 4:1 and 200:1, the outer skin having greater conductively than the inner portion.

2. The assembly of claim 1 wherein the second width is between 20 microns and 50 microns.

3. The assembly of claim 1 wherein the second width is between 25 microns and 35 microns.

4. The assembly of claim 1 wherein the second width is 30microns.

5. The assembly of claim 1 wherein the width ratio is 120:1.

6. The assembly of claim 1 wherein the inner portion comprises one of aluminum and copper.

7. The assembly of claim 1 wherein the lamination stack comprises steel alloy.

8. A method of making a cast induction rotor assembly for a vehicle, the method comprising:
providing a lamination stack comprising a body having a first end and an opposing second end to define a longitudinal axis, the body having an outer circumferential portion extending from the first end to the second end coaxial with the longitudinal axis, the outer circumferential portion having a plurality of walls defining open slots formed therethrough from the first end through the second end;
disposing an outer skin on each of the plurality of walls, each outer skin extending continuously from the first end to the second end along the longitudinal axis, the outer skin having carbon nanotubes disposed thereon in a predetermined orientation for conductivity;
providing a negative cast mold having first cavities to form a first ring arranged to be disposed on the first end and second cavities to form a second ring arranged to be disposed on the second end;
engaging the lamination stack with the negative cast mold such that the first cavities are in coaxial alignment with the first end and the second cavities are in coaxial alignment with the second end, the first cavities being in fluid communication with the second cavities;
melting a first metallic material at a predetermined temperature to define a molten metallic material;
feeding the molten metallic material in the negative cast mold to fill the first and second cavities;
cooling the molten metallic material to form a solidified metallic material in the negative cast mold having dimensions of the cast induction rotor assembly, the solidified metallic material defining a plurality of conductive bars connecting the first and second rings, each conductive bar disposed in one of the open slots and extending from the first ring to the second ring, each conductive bar comprising an inner portion and one of the outer skins disposed on the respective wall, the inner portion being disposed within the respective outer skin, the inner portion comprising the solidified metallic material, the inner portion having a first width and the outer skin having a second width to define a width ratio of the first width to the second width of between 4:1 and 200:1, the outer layer skin having greater conductively than the inner portion; and
separating the solidified metallic material from the negative cast mold to define the cast induction rotor assembly.

9. The method of claim 8 wherein the first cavities are in fluid communication with the second cavities by way of the open slots and wherein feeding the molten metallic material in the negative cast mold comprises feeding the molten metallic material through the open slots.

10. The method of claim 8 wherein disposing the outer skin on each of the plurality of walls comprises wrapping each outer skin about a metallic bar to define a plurality of coated bars, each coated bar disposed in one of the open slots.

11. The method of claim 10 wherein further comprising:
providing a plurality of ingates disposed on the negative cast mold and in fluid communication with the first cavities; and
providing a plurality of runners to connect the first cavities and the second cavities such that the first and second cavities are in fluid communication.

12. The method of claim 11 wherein feeding the molten metallic material in the negative cast mold comprises feeding the molten metallic material through the plurality of ingates and the plurality of runners to fill the first and second cavities.

13. The method of claim 8 further comprising:
prior to feeding the molten metallic material in the negative cast mold, preheating the lamination stack to between 150 degree Celsius (° C.) and 400° C.

14. The method of claim 10 wherein the first metallic material comprises one of aluminum and copper and wherein the metallic bar comprises the first metallic material.

15. The method of claim 8 wherein the predetermined temperature is between 650° C. and 900° C.

16. The method of claim 8 wherein the second width is between 20 microns and 50 microns and wherein the width ratio is 120:1.

17. The method of claim 8 wherein the lamination stack comprises steel alloy.

18. A system for making a cast induction rotor assembly of a vehicle, the system comprising:
a lamination stack comprising a body having a first end and an opposing second end to define a longitudinal axis, the body having an outer circumferential portion extending from the first end to the second end coaxial with the longitudinal axis, the outer circumferential portion having a plurality of walls defining open slots formed therethrough from the first end through the second end;
an outer skin disposed on each of the plurality of walls, each outer skin extending continuously from the first end to the second end along the longitudinal axis, the outer skin having carbon nanotubes disposed thereon in a predetermined orientation for conductivity;
a negative cast mold having first cavities to form a first ring arranged to be disposed on the first end and second cavities to form a second ring arranged to be disposed on the second end;
an engaging unit arranged to engage the lamination stack with the negative cast mold such that the first cavities are in coaxial alignment with the first end and the second cavities are in coaxial alignment with the second end, the first cavities being in fluid communication with the second cavities;
a furnace arranged to melt a first metallic material at a predetermined temperature to define a molten metallic material;
a feeding mechanism disposed about the negative cast mold and in fluid communication with the first and second cavities thereof, the feeding mechanism arranged to feed the molten metallic material in the negative cast mold to fill the

Assignees

• Gm Global Tech Operations Llc

Inventors

• Wang Qigui
• Agapiou John S
• Wang Liang
• Hao Lei
• Wilson Daniel J
• Burkholder Steven L

Classifications

• H02K15/021 Primary

  Magnetic cores · CPC title

• H02K15/023 Primary

  Cage rotors · CPC title

• H02K17/20

  having deep-bar rotors · CPC title

• H02K1/26 Primary

  Rotor cores with slots for windings · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title