Patent ID: 8020280

Claim:
A rotor manufacturing method comprising: a preparation step of placing a lower surface of a hollow cylindrical rotor core on a lower mold, the rotor core being made of a plurality of electromagnetic steel sheets formed with dowels and laminated with the dowels being engaged with each other; an insertion step of inserting magnets in a plurality of magnet containing holes axially formed through the rotor core so that a predetermined space is provided between an upper surface of the rotor core and an upper surface of each magnet; and a molding step of placing an upper mold on the upper surface of the rotor core to allow communication between a lower end of each cylinder provided to extend to a lower surface in the upper mold and the magnet containing hole through a communication path formed in the lower surface of the upper mold, pressurizing the rotor core by the upper and lower molds, pushing molten resin out of each cylinder by a plunger to supply the molten resin with pressure into each magnet containing hole through the communication path and the predetermined space, and fixing the magnets in the rotor core by resin molding; wherein the molding step includes supplying the molten resin with pressure from each cylinder of the upper mold into the plurality of magnet containing holes from one of an inner periphery side and an outer periphery side to mold the magnets with the resin while pressing the magnets toward one of the outer periphery side and the inner periphery side in each magnet containing hole.