| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve higher efficiency and lower cost by improving an impeller. <P>SOLUTION: A method for manufacturing the closed impeller includes: forming a frustum-shaped front plate 1 and a disk-shaped base plate 3 formed therebelow; forming upper surfaces of unit impeller blade plates 21 made of a hard synthetic resin extending in a plurality of radial directions, as impeller blade tip surfaces 21a; and providing impeller blades 2 with sharp-pointed ridge-like protrusions 4 having an acute upper end and a width less than a width of the impeller blade tip surface being integrally formed on the impeller blade tip surfaces 21a. The method further includes: forming an inner surface 1b of the front plate 1 and the plurality of impeller blade tip surfaces 21a as parts of conical surfaces and such that the cone apex angles of the two conical surfaces are equal to each other; placing the front plate 1 on the impeller blade 2 and bringing the ends of the sharp-pointed ridge-like protrusions 4 and the inner surface 1b of the front plate 1 into contact with each other; giving small vibrations while applying an appropriate pressing force between the front plate 1 and the impeller blade 2 having the base plate 3 attached thereto; and melting the sharp-pointed ridge-like protrusions 4 to weld the front plate 1 to the impeller blade 2. <P>COPYRIGHT: (C)2011,JPO&INPIT |
