| 摘要 |
PURPOSE:To enable to manufacture a squirrel-cage rotor having a vent gap by low pressure casting in high quality by press-fitting molten metal while applying an ultrasonic vibration to a core and a mold when press-fitting the molten metal to a laminated core between which a vent gap forming piece is interposed. CONSTITUTION:A core block 3c formed by laminating punched plates 4 and vent gap forming pieces 1 are alternately laminated, a shaft 5 is inserted into the shaft hole 3a of the center, and molds 7, 8 are mounted thereon and thereunder. Molten metal 15 such as aluminum is press-fitted from below the mold 8 to the end ring 10 and the slot 3b of a core in the mold to integrally mold a squirrel-cage rotor. In this case, the metal 15 is press-fitted while applying an ultrasonic wave vibration from an ultrasonic wave generator 13 at least part of the core 3c, the molds 7, 8 and the shaft 5. Thus, since the solidifying speed difference between the core 3c and the piece 1 can be eliminated, casting defect can be prevented. |
