Patent ID: 7854056

Claim:
A method of producing a rotor, comprising: providing a hollow cylindrical rotor core constituted of laminated electromagnetic steel sheets; a slot that is a hole axially formed through the rotor core and arranged near a peripheral edge of the rotor core; a magnet, having an end surface and a side surface, placed in the slot; an upper die provided with a cylinder through which molten resin is to be injected and placed on a first end surface of the rotor core such that the cylinder communicates with the slot via a communication area between the end of the cylinder and the first end surface of the rotor core; and a lower die placed on a second end surface of the rotor core for pressurizing the rotor core in cooperation with the upper die; and fixing the magnet to the rotor core by injecting the molten resin into the slot by injection molding, wherein: a dimension between the first end surface of the rotor core and the end surface of the magnet is a core end surface-magnet interval, δ, a dimension between an inner surface of the slot and the side surface of the magnet is a slot-magnet interval, α, a minimum slot magnet interval value is a minimum value of the slot-magnet intervals of a plurality of verification objects having different slot-magnet intervals, as determined by allowing molten resin to-fully fill the space between an inner surface of a test slot of each verification object and a side surface of a test magnet of each verification object up to a portion of the test slot next to a test lower die of each verification object when injecting the resin into the test slot through a test cylinder of an upper die of each verification object, and a value of the core end surface-magnet interval, δ, is larger than the minimum slot-magnet interval value.