Rotor for electric motor
A rotor for an electric motor includes a rotor core defining a plurality of slots that are spaced apart from each other and arranged along a circumferential direction of the rotor core, and a rotor winding provided at the plurality of slots and configured to flow current. The rotor winding includes a plurality of conductor bars that extend in an axial direction of the rotor core and that are disposed in a slot of the plurality of slots, and end rings that are disposed at both sides of the plurality of conductor bars and that connect the plurality of conductor bars to each other. The rotor further includes deformation preventing units each of which surrounds and contacts an outer surface of one of the end rings. The deformation preventing units are configured to restrict deformation of the end rings.
1. A rotor for an electric motor, the rotor comprising:
a rotor core defining a plurality of slots that are spaced apart from each other and arranged along a circumferential direction of the rotor core;
a rotor winding provided at the plurality of slots and configured to flow current, the rotor winding comprising:
a plurality of conductor bars that are made of aluminum, each conductor bar extending in an axial direction of the rotor core and being disposed in a slot of the plurality of slots, and
end rings that are made of aluminum, that are disposed at both sides of the plurality of conductor bars, and that connect the plurality of conductor bars to each other, each of the end rings including a protrusion that protrudes from an end surface spaced apart from one of the sides of the plurality of conductor bars in the axial direction of the rotor core; and
deformation preventing units that are configured to restrict deformation of the end rings, each deformation preventing unit surrounding and contacting an outer surface of one of the end rings,
wherein the outer surface of the end rings is disposed radially inward of an outer surface of the plurality of conductor bars, and
wherein each of the deformation preventing units comprises:
a body portion having a ring shape and surrounding the outer surface of one of the end rings, and
a protrusion coupling portion extending from the body portion in a radial direction of the rotor core and coupling to the protrusion.
2. The rotor of claim 1 , wherein a thermal expansion coefficient of the deformation preventing units is less than that of the end rings to restrict radial deformation of the end rings.
3. The rotor of claim 1 , wherein the protrusion coupling portion defines a through hole that receives the protrusion, and
wherein the protrusion includes a head portion having a diameter greater than the through hole and configured to restrict axial movement of the deformation preventing units.
4. The rotor of claim 3 , wherein the head portion is configured to extend outside the through hole by pressing the head portion in the axial direction based on the protrusion having been inserted in the through hole.
5. The rotor of claim 1 , wherein the protrusion includes a plurality of protrusions that are spaced apart from each other and arranged along the circumferential direction on the end surface of one of the end rings, and
wherein the end rings further include a protruding portion that protrudes from the end surface in the axial direction and is disposed on at least one side of each of the plurality of protrusions.
6. The rotor of claim 5 , wherein the protruding portion includes a plurality of protrusion portions, each protrusion portion being disposed between a pair of protrusions.
7. The rotor of claim 1 , wherein an outer diameter of the rotor core is greater than an outer diameter of each of the end rings.
8. A rotor for a motor, the rotor comprising:
a rotor core defining a plurality of slots that are spaced apart from each other and arranged along a circumferential direction of the rotor core;
a rotor winding provided at the plurality of slots and configured to flow current, the rotor winding comprising:
a plurality of conductor bars that are made of aluminum, each conductor bar extending in an axial direction of the rotor core and being disposed in a slot of the plurality of slots, and
end rings that are made of aluminum, that are disposed at both sides of the plurality of conductor bars, and that connect the plurality of conductor bars to each other, each of the end rings including a protrusion that protrudes from an end surface spaced apart from one of the sides of the plurality of conductor bars in the axial direction of the rotor core; and
deformation preventing units configured to restrict deformation of the end rings, each deformation preventing unit surrounding and contacting an outer surface of one of the end rings,
wherein the outer surface of the end rings is disposed radially inward of an outer surface of the plurality of conductor bars,
wherein each of the end rings further includes a protruding portion that protrudes from the end surface in the axial direction of the rotor core, and
wherein each of the deformation preventing units comprises:
a body portion having a ring shape and surrounding the outer surface of one of the end rings, and
a coupling portion extending from the body portion in a radial direction of the rotor core and coupling to the protruding portion.
9. The rotor of claim 8 , wherein the protruding portion includes a separation preventing unit that protrudes from a surface of the protruding portion and that is configured to restrict separation of the protruding portion from the coupling portion based on the protruding portion being coupled to the coupling portion.
10. The rotor of claim 9 , wherein the protruding portion couples to the coupling portion in the axial direction, and
wherein the separation preventing unit includes a separation preventing protrusion that extends in the axial direction.
11. The rotor of claim 8 , wherein the protruding portion defines a side surface that slopes with respect to the radial direction of the rotor core by a predetermined inclination angle.
12. The rotor of claim 8 , wherein the protruding portion includes a plurality of protruding portions that are spaced apart from each other and arranged along the circumferential direction on the end surface of one of the end rings, and
wherein the coupling portion includes a plurality of coupling portions that couple to the plurality of protruding portions, respectively.
13. The rotor of claim 8 ,
wherein an outer diameter of the deformation preventing units is less than or equal to an outer diameter of the rotor core.
14. The rotor of claim 8 , wherein a width of the end rings in the axial direction is greater than a width of the deformation preventing units in the axial direction.
15. The rotor of claim 8 , wherein the rotor core defines a plurality of penetrating portions that extend through the rotor core in the axial direction and that allow flow of air or liquid through the penetrating portions,
wherein the plurality of penetrating portions are disposed radially inward of the outer surface of the deformation preventing units.
16. The rotor of claim 8 , wherein the slot includes an outer surface and an inner surface disposed radially inward of the outer surface of the slot, and
wherein a width of the outer surface of the slot is greater than that of the inner surface of the slot.
17. The rotor of claim 8 ,
wherein the protrusion comprises a plurality of protrusions that protrude from the end surface in the axial direction and that are arranged in the circumferential direction of the rotor core, and
wherein the protruding portion comprises a plurality of protruding portions that protrude from the end surface and that are alternately disposed between the plurality of protrusions.