Squirrel-cage motor rotor and squirrel-cage motor

1. A squirrel-cage motor rotor comprising:

conductor bars respectively filling a plurality of slot holes penetrating a rotor core in an axial direction and provided at regular intervals along a circumferential direction of the rotor core;

short-circuit rings connected to ends of the conductor bars; and

reinforcement covers having axial-direction surfaces which come in contact with axial-direction-end surfaces of the short-circuit rings, the reinforcement covers having a hole at a center, wherein

the conductor bars and the short-circuit rings are integrally formed by casting,

the reinforcement covers are cylindrical members having body portions and annular flange portions vertically protruding from outer circumferential surfaces on one axial-direction-end side of the body portions,

outer circumferential surfaces of the body portions and inner circumferential surfaces of the short-circuit rings are in contact with each other,

axial-direction surfaces of the flange portions are in contact with the axial-direction-end surfaces of the short-circuit rings, and

holding rings are attached by interference fit such that inner circumferential surfaces thereof are in contact with outer circumferential surfaces of the flange portions and outer circumferential surfaces of the short-circuit rings.

2. The squirrel-cage motor rotor according to claim 1 , wherein

the reinforcement covers are enclosed by casting in the short-circuit rings, and

the flange portions have short-circuit ring projection insertion holes formed at positions opposed to the conductor bars.

3. The squirrel-cage motor rotor according to claim 1 , wherein

the short-circuit rings are attached to the body portions by interference fit.

4. The squirrel-cage motor rotor according to claim 1 , wherein

inner circumferential surfaces of the reinforcement covers and an inner circumferential surface of the rotor core are attached so as to come in contact with an outer circumferential surface of a rotor shaft by interference fit.

5. The squirrel-cage motor rotor according to claim 1 , wherein

the reinforcement covers have annular flange portions vertically protruding from outer circumferential surfaces on another axial-direction-end side of the body portions.

6. A squirrel-cage motor comprising:

the squirrel-cage motor rotor according to claim 1 ; and

a stator provided so as to be opposed to the rotor.

7. A squirrel-cage motor rotor comprising:

conductor bars respectively filling a plurality of slot holes penetrating a rotor core in an axial direction and provided at regular intervals along a circumferential direction of the rotor core;

short-circuit rings connected to ends of the conductor bars; and

reinforcement covers having axial-direction surfaces which come in contact with axial-direction-end surfaces of the short-circuit rings, the reinforcement covers having a hole at a center, wherein

the conductor bars and the short-circuit rings are integrally formed by casting,

the reinforcement covers have, in a plan view, a doughnut disk shape which is the same as a shape of the axial-direction-end surfaces of the short-circuit rings, and have short-circuit ring projection insertion holes formed at positions opposed to the conductor bars,

reinforcement rings are attached by interference fit such that outer circumferential surfaces thereof are in contact with inner circumferential surfaces of the reinforcement covers and inner circumferential surfaces of the short-circuit rings, and

holding rings are attached by interference fit such that inner circumferential surfaces thereof are in contact with outer circumferential surfaces of the reinforcement covers and outer circumferential surfaces of the short-circuit rings.

8. The squirrel-cage motor rotor according to claim 7 , wherein

inner circumferential surfaces of the reinforcement rings and an inner circumferential surface of the rotor core are attached so as to come in contact with an outer circumferential surface of a rotor shaft by interference fit.

9. A squirrel-cage motor comprising:

the squirrel-cage motor rotor according to claim 7 ; and

a stator provided so as to be opposed to the rotor.

10. A squirrel-cage motor rotor comprising:

conductor bars respectively filling a plurality of slot holes penetrating a rotor core in an axial direction and provided at regular intervals along a circumferential direction of the rotor core;

short-circuit rings connected to ends of the conductor bars; and

reinforcement covers having axial-direction surfaces which come in contact with axial-direction-end surfaces of the short-circuit rings, the reinforcement covers having a hole at a center, wherein

the conductor bars and the short-circuit rings are integrally formed by casting,

the reinforcement covers are cylindrical members having body portions and annular flange portions vertically protruding from inner circumferential surfaces on one axial-direction-end side of the body portions, and are attached by interference fit such that axial-direction surfaces of the flange portions are in contact with the axial-direction-end surfaces of the short-circuit rings, and inner circumferential surfaces of the body portions are in contact with outer circumferential surfaces of the short-circuit rings, and

reinforcement rings are attached by interference fit such that outer circumferential surfaces thereof are in contact with inner circumferential surfaces of the flange portions and inner circumferential surfaces of the short-circuit rings.

11. The squirrel-cage motor rotor according to claim 10 , wherein

inner circumferential surfaces of the reinforcement rings and an inner circumferential surface of the rotor core are attached so as to come in contact with an outer circumferential surface of a rotor shaft by interference fit.

12. A squirrel-cage motor comprising:

the squirrel-cage motor rotor according to claim 10 ; and

a stator provided so as to be opposed to the rotor.