SCREW TYPE ROTARY MACHINE, ITS ROTOR SURFACE TREATMENT, AND DRY SYSTEM SCREW TYPE ROTARY MACHINE AND ITS ROTOR SURFACE TREATMENT

摘要

PURPOSE:To improve abrasion resistance, corrosion resistance, and close adhesiveness by applying surface treatment, consisting of a plurality of layers for covering a film consisting of organic resin, to the electroless Ni plating applied to one or both of the male rotor and female rotor which are engaged with each other. CONSTITUTION:The male rotor 1 and female rotor 2 of a screw type vacuum pump are both made of spheroidal graphite cast iron (FCD55), and the surface is given surface treatment. Accordingly, the surfaces of both rotors 1 and 2 are coated with electroless Ni plating, and after the heating for a prescribed time, cooling is carried out, and a crank is generated on the electroless Ni plating 4. In this state, heating is carried out again, and the surface of the electroless Ni plating 4 is covered with polyphenylene sulfide resin 5 through injection molding, and both 4 and 5 are closely attached by the anchor effect, and integrally formed. Then, the surface of the resin 5 is covered with a film 6 consisting of epoxy resin, etc., by the electrodeposition method, and surface treatment is completed.