Patent ID: 8881393

Claim:
A manufacturing method of an impeller for a fluid transmitting device, the impeller including an annular, bowl-shaped shell, a plurality of blades joined to an inner surface of the shell and arranged in a peripheral direction of the shell, and a core having a convex outer surface brazed to intermediate portions of the blades so as to couple the intermediate portions of the blades to each other, the manufacturing method comprising: a first step of disposing the core horizontally with a concave inner surface of the core facing up in a state where coupling pieces provided to the blades are fitted in positioning holes provided to the core, respectively; a second step of disposing a brazing material on the inner surface of the core; a third step of melting the brazing material and causing the molten brazing material to penetrate into gaps between the coupling pieces and positioning holes that are fitted to each other and further into gaps between the core and the blades; and a fourth step of solidifying the molten brazing material having penetrated into the gaps, wherein a plurality of guide grooves aligned in the peripheral direction to allow communication between adjacent ones of the plurality of positioning holes are provided in the concave inner surface of the core in advance, and in the third step, the molten brazing material is guided to the positioning holes through the plurality of the guide grooves.