End-ring for induction motor, rotor having the same

A rotor comprising:

• a rotor core configured to rotate about a rotation axis and extending between a first end and a second end along an axial direction parallel to the rotation axis, the rotor core comprising a plurality of slots arranged in an angular direction about the rotation axis;
• a plurality of rotor bars, each of which is inserted in the plurality of slots, the plurality of rotor bars comprising a first rotor bar, a second rotor bar and a third rotor bar arranged in order along the angular direction such that the second rotor bar immediately neighbors the first rotor bar and the third rotor bar and is interposed between the first rotor bar and the third rotor bar when viewed in the axial direction, each of the plurality of rotor bars comprising a first end portion extending beyond the first end of the rotor core;
• and
• a plurality of single piece holders arranged along the angular direction and coupled to the first end portions of the plurality of rotor bars, the plurality of holder comprising a first holder and a second holder immediately neighboring the first holder along the angular direction;
• wherein, when viewed in the axial direction, each single piece holder comprises a base portion, a first branch protruding radially outward from the base portion, a second branch protruding radially outward from the base portion, and an insertion groove formed radially outside the base portion and between the first branch and the second branch, the insertion groove receiving the first end portion of one of the plurality of rotor bars,
• wherein, when viewed in the axial direction, the first rotor bar is received in the insertion groove of the first holder, the third rotor bar is received in the insertion groove of the second holder, the second rotor bar is positioned in a gap between the first holder and the second holder immediately neighboring the first holder.