Twin-screw compressor rotors are effectively helical gears. When these are formed from a hobbing cutter, the hobbing tool and the rotor together constitute a pair of crossed helical gears. In the present paper, the envelope gearing method is used to derive a meshing condition for crossed helical gears which is then used to create the profile of a hobbing tool. A reverse transformation enables the rotor profile thereby manufactured to be calculated. Simplification of the main gearing condition leads to the meshing expression for helical gears which may be used for the design of screw compressor rotors.
TangY.Computer aided design of twin screw compressors. PhD thesis, University of Strathclyde, Glasgow, 1995.
4.
StošiçN.HanjalićK.Development and optimization of screw machines with a simulation model. Part 1: Profile generation. Trans. ASME, J. Fluids Engng, 1997, 119, 695–663.
5.
ColburneJ. R.The Geometry of Involute Gears, 1987 (Springer, New York).
