JPS57191496A - Impeller for use in fan and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture an impeller, light, economical and having a high performance, by forming a blade having a required shape by way of bulging by expanding a prefabricated bag-like plate from the inside thereof by use of a pressurizing medium. CONSTITUTION:The inner space of a prefabricated bag-like plate 7 is pressurized beforehand (for instance, to 4-5atm) by injecting nitrogen gas into the inner space of the plate 7 from a gas injection port 10, so that the bag-like plate 7 can be protected against buckling when it is fixed between an upper and a lower molds 5 and 6. When the upper mold 5 is lowered to a required position by means of a press head (not shown) while heating the bag-like plate 7 by supplying current to embedded heaters 11, the upper mold 5 is lowered together with an upper and a lower retainers 8, 9 to a position where it is held in abutment with the lower mold 6. In this state, a bulging pressure (for instance, 40atm) is imparted to the inner space of the bag-like plate 7 by raising the pressure of nitrogen gas so as to shape the surfaces of the bag-like plate 7 into the configuration of molding surfaces 5a, 6a of the upper and the lower molds 5, 6. By thus completing the bulging operation, it is enabled to manufacture an impeller, light, economical and having a high performance.