IMPELLER WITH SHROUD

PROBLEM TO BE SOLVED: To prevent an impeller from being subjected to tension in such a way that it can withstand high speed revolution, and enhance the stiffness of whole the structure. SOLUTION: A shroud in a cone shape is formed out of a CFRP laminated plate 12 comprising long fiber CFRP prepreg 11 liminated. An impeller main body 13 having a boss 14 and blades 15, is formed out of short fiber reinforced resin. The shroud 10 is joined with the outer side of the impeller main body 13 so as to be integrated therewith. Since the shroud 10 formed out of the CFRP laminated plate 12 made of longer fibers is higher in stiffness than the impeller main body 13 formed out of short fiber reinforced CFRP, let compression stress be incurred in each blade 15 just because of the difference in stiffness between both of them, by letting the shroud 10 act as a hoop. Besides, a CFRP laminated plate 16 is joined with the base end surface of the boss 14 so as to allow the base end part of the impeller main body 13 to be high in stiffness.