Gear-Cutting Tool for Screw-Compressor Rotors (Built-up Hob)

摘要

A built-up hob for a screw-compressor rotor is proposed. The hob is composed of cutter blades and a hob head. The blade is cut out from a tempering planar plate of high speed tool steel by wire -cut electric discharge machining. During the wire cutting process, the wire electrode has a fixed angle to ensure both the side and the end relief angle of the cutting edge, so that the rake face regrinding sharpens the cutting edge without changing the profile of the rake face. The formulae of rack tooth profile are derived from the female rotor tooth profile expressed by numerical formulae. Then, the fundamental helicoid of the hob and the profile of the cutting edge of the blade are calculated. The hob was made and the rotor hobbing was carried out.