Patent ID: 8435005

Claim:
A manufacturing method of an impeller, which includes a disc, a cover opposed to the disc, a plurality of blades between the disc and the cover, and a plurality of passages between the disc and the cover, each of the plurality of passages having an inlet on a surface of the cover of the impeller and an outlet on an outer peripheral surface of the impeller, and the direction of each of the plurality of passages being changed so as to follow a radial direction of the impeller as each of the plurality of passages proceeds from the inlet to the outlet, the manufacturing method comprising: forming the plurality of blades integrally on a blade attachment surface of one of the disc and the cover; placing the cover on a floor so that the blade attachment surface of the cover faces in an upward direction; disposing the disc on the cover so the blade attachment surface of the disc faces in a downward direction; bonding the plurality of blades to the blade attachment surface of the other of the disc and the cover which is not formed integrally with the plurality of blades using a bonding material; and for each passage of the plurality of passages, forming an uneven portion proximal to an inner peripheral bond part end at a curved portion of the passage, in a bond part with the blades, on the blade attachment surface of the cover so as to prevent the bonding material from spilling.