Rotor, electric motor, air conditioner, and method for manufacturing rotor

A method for manufacturing a rotor including an annular yoke portion having a first inner circumferential surface, a second inner circumferential surface adjacent to the first inner circumferential surface, and a third inner circumferential surface adjacent to the second inner circumferential surface, the method comprising the steps of:

• forming the first inner circumferential surface, the second inner circumferential surface having a radius larger than a radius of the first inner circumferential surface, and the third inner circumferential surface having a radius larger than both of the radius of the first inner circumferential surface and the radius of the second inner circumferential surface, by injecting a thermoplastic resin into a mold including a runner into which the thermoplastic resin is injected and a molding portion to mold the thermoplastic resin into the yoke portion;
• and
• separating a first part formed in the runner from a second part formed in the molding portion.