METHOD FOR MOLDING IMPELLER OF CENTRIFUGAL HYDRAULIC MACHINERY AND MOLD USED THEREFOR

PURPOSE:To stabilize the quality of an impeller and make it possible to perform the inspection of molded item by sampling and consequently to reduce the inspection man-hours by a method wherein molten resin passed through a sprue and gates is made to simultaneously start to flow from the mouthring and boss part of an impeller so as to well-balancedly and equally fill the cavities for a main plate and for a side plate. CONSTITUTION:When the injection molding of a resin impeller 6 is intended, after a top and a bottom forces 5 and 4 are clamped together, molten resin is injected from an inlet 7 into the forces so as to flow the molten resin through a sprue 8 and runners 21 out of respective pin gates 22 and 23, which are provided in the same number as the number of vanes, into the boss part 17 of the impeller and the mouthring 15a part of a side plate 15 simultaneously in order to be equally filled in the cavities 4a and 4b, which correspond to a main plate 16 and to the side plate 15 respectively. Thus, no excessive force, which deforms a core formed piece 1, is applied, resulting in realizing well-balanced molding and allowing to obtain the molded item 6 of a centrifugal impeller with the thickness of specified dimensions.