US Patent No. 9,263,929

SQUIRREL-CAGE ROTOR AND ELECTRIC MOTOR HAVING SQUIRREL-CAGE ROTOR


Patent No. 9,263,929
Issue Date February 16, 2016 
Title Squirrel-cage Rotor And Electric Motor Having Squirrel-cage Rotor
Inventorship Yohei Arimatsu, Yamanashi (JP)
Assignee Fanuc Corporation, Yamanashi (JP)

Claim of US Patent No. 9,263,929

1. A squirrel-cage rotor comprising:
a rotational axis extending in an axial direction;
a laminated core provided on an outer circumference of the rotational axis; and
a plurality of slots arranged in the laminated core so as to be spaced apart from each other in a circumferential direction,
and extending in the axial direction,

wherein each slot is a closed slot whose entire circumference is closed by the laminated core, and has a sectional shape in
a direction perpendicular to the axial direction,

wherein the sectional shape of each slot includes:
an inner circumferential edge and an outer circumferential edge, each of which extends in the circumferential direction of
the laminated core;

a first side portion and a second side portion, each of which extends in a radial direction of the laminated core;
a first curved corner connecting the inner circumferential edge to the first side portion;
a second curved corner connecting the inner circumferential edge to the second side portion;
a third curved corner connecting the outer circumferential edge to the first side portion; and
a fourth curved corner connecting the outer circumferential edge to the second side portion,
wherein the inner circumferential edge has a radius of curvature greater than that of the first curved corner and the second
curved corner, the inner circumferential edge protruding inwardly in the radial direction, and

wherein the outer circumferential edge has a radius of curvature greater than that of the third curved corner and the fourth
curved corner, the outer circumferential edge protruding outwardly in the radial direction.