LIMITING RADIAL EXPANSION IN ROTOR BALANCING

• US 20140368082A1
• Filed: 06/17/2013
• Published: 12/18/2014
• Est. Priority Date: 06/17/2013
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Barton, Augusto E.
• Granted Patent: US 9,729,032 B2
• Time in Patent Office: Days
• US Class Current: 310/216.121
• CPC Class Codes: H02K 15/165 Balancing the rotor
• CPC Class Codes: H02K 17/165 characterised by the squirrel-cage or other short-circuited windings
• CPC Class Codes: H02K 17/20 having deep-bar rotors
• CPC Class Codes: H02K 7/04 Balancing means
• CPC Class Codes: Y10T 29/49012 Rotor

Abstract

A rotor including: a shaft; a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon a rotor balancing process that involves spinning of the structure; a core that at least partially encloses the rotor bars; and means for limiting the expansion or movement of the structure radially outward. A method including: providing a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon spinning of the structure; assembling a rotor from the structure and a core, the core at least partially enclosing the rotor bars; spinning the rotor in a rotor balancing process; and limiting the expansion or movement of the structure radially outward in the rotor balancing process.

Claims

1. A rotor comprising:

a shaft;

a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon a rotor balancing process that involves spinning of the structure;

a core that at least partially encloses the rotor bars; and

means for limiting the expansion or movement of the structure radially outward.

2. The rotor of claim 1, wherein the means comprises a protrusion on one of the structure and the core, and a slot on another of the structure and the core, wherein a gap initially exists between a radially outermost portion of the protrusion and a radially outermost surface of the slot, and wherein the expansion or movement radially outward of the structure is limited when the radially outermost portion of the protrusion contacts the radially outermost surface of the slot.

3. The rotor of claim 2, wherein the radially outermost portion of the protrusion has a common curvature with the radially outermost surface of the slot.

4. The rotor of claim 3, wherein the means comprises three protrusion-slot pairs spaced equally from each other.

5. The rotor of claim 4, wherein the protrusion is on the end ring and the slot is on the core.

6. The rotor of claim 5, wherein the core comprises a stack of laminations and the slot comprises an opening through at least an outermost one of the laminations.

7. The rotor of claim 1, wherein the core fully encloses the rotor bars within bar slots, wherein the means comprises a group of the rotor bars being positioned in a group of the bar slots that extend less far radially from the shaft than others of the bar slots, and wherein the expansion or movement of the structure radially outward is limited when each of the group of the rotor bars contacts a corresponding one of the group of the bar slots.

8. The rotor of claim 7, wherein each of the group of the rotor bars is identical to remaining rotor bars.

9. The rotor of claim 7, wherein the group of the bar slots is three bar slots spaced equally from each other.

10. The rotor of claim 1, wherein the material primarily consists of copper and the core primarily consists of steel.

11. A method comprising:

providing a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon spinning of the structure;

assembling a rotor from the structure and a core, wherein the core at least partially encloses the rotor bars;

spinning the rotor in a rotor balancing process; and

limiting the expansion or movement of the structure radially outward in the rotor balancing process.

12. The method of claim 11, wherein one of the structure and the core comprises a protrusion, and another of the structure and the core rotor comprises a slot, wherein a gap initially exists between a radially outermost portion of the protrusion and a radially outermost surface of the slot, and wherein limiting the expansion or movement of the structure radially outward comprises contacting the radially outermost portion of the protrusion with the radially outermost surface of the slot.

13. The method of claim 11, wherein the core fully encloses the rotor bars within bar slots, wherein a group of the rotor bars is positioned in a group of the bar slots that extend less far radially from the shaft than others of the bar slots, and wherein limiting the expansion or movement of the structure radially outward comprises each of the group of the rotor bars contacting a corresponding one of the group of the bar slots.